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Claims  |
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We claim:
1. A user interface for depiction on a graphical display surface,
comprising:
an interactive road map displayed on the graphical display surface, the
interactive road map showing a plurality of road segments that are
interactively selectable by a user on the graphical display surface;
a road image area displayed on the graphical display surface alongside the
interactive road map, wherein the road image area changes as the user
selects different road segments to show recent images of a currently
selected road segment.
2. A user interface as recited in claim 1, wherein the recent images shown
in the road image area are recent video clips of the currently selected
road segment.
3. A computer and associated display device, the computer being programmed
to implement the user interface of claim 1.
4. A computer-readable medium having computer-executable instructions for
implementing the user interface of claim 1 in conjunction with a display
device having a graphical display surface.
5. A user interface as recited in claim 1, wherein the recent images are
still images.
6. A user interface as recited in claim 1, wherein different recent images
of a particular road segment are cycled in the road image area when the
particular road segment remains selected.
7. A user interface as recited in claim 1, the user interface being
responsive to a command from the user to cycle historical images of the
selected road segment in the road image area at defined intervals.
8. A user interface as recited in claim 1, the user interface accepting a
starting location and a destination location from the user and in response
indicating a shortest-time route from the starting location to the
destination location based on current travel times of the road segments.
9. A user interface for depiction on a graphical display surface,
comprising:
a road map showing a plurality of road segments that a user can
interactively select;
a road image area that changes as the user selects different road segments
to show recent images of a currently selected road segment;
the user interface being responsive to a command from the user to show a
detail map of a particular selected road segment, wherein the detail map
includes road sub-segments of the particular road segment that the user
can interactively select;
wherein the road image area shows recent images of a currently selected
road sub-segment.
10. A user interface as recited in claim 1, further comprising a traffic
description relevant to a particular road segment, the traffic description
being depicted on the graphical display surface when said particular road
segment is selected by the user.
11. A user interface as recited in claim 10, wherein the traffic
description includes the current average speed for the particular road
segment.
12. A user interface as recited in claim 10, wherein the traffic
description includes the current travel time for the particular road
segment.
13. A user interface as recited in claim 10, wherein the traffic
description can be designated by the user to include at least one of the
current travel time and the current average speed for the particular road
segment.
14. A computer-readable medium having computer-executable instructions for
performing steps comprising:
obtaining current traffic data for a plurality of road segments;
displaying an interactive road map to a user on a graphical display
surface, the interactive road map showing the plurality of road segments
that are interactively selectable by a user on the graphical display
surface;
allowing a user to individually select road segments on the interactive
road map by interactively selecting road segments on the graphical display
surface;
displaying recent images of the currently selected road segment alongside
the interactive road map on the graphical display surface.
15. A computer-readable medium as recited in claim 14 wherein the recent
images are recent video clips of the currently selected road segment.
16. A computer-readable medium as recited in claim 14 wherein the recent
images are recent video clips of the currently selected road segment, the
computer-readable medium having further instructions for performing an
additional step of cycling historical video clips of the selected road
segment at defined intervals in response to a user's request.
17. A computer-readable medium as recited in claim 14 having further
instructions for performing an additional step of cycling different recent
images of a particular road segment when the particular road segment
remains selected.
18. A computer-readable medium as recited in claim 14 having further
instructions for performing an additional step of cycling historical
images of the selected road segment at defined intervals in response to a
user's request.
19. A computer-readable medium having computer-executable instructions for
performing steps comprising:
obtaining current traffic data for a plurality of road segments;
displaying a road map to a users, the road map showing the plurality of
road segments;
allowing a user to individually select road segments on the road map;
displaying recent images of the currently selected road segment alongside
the road map;
showing a detail map of a particular selected road segment in response to a
command from the user, wherein the detail map includes road sub-segments
of the particular road segment;
allowing a user to select a starting road sub-segment on the detail map;
allowing a user to select a destination road sub-segment on the detail map;
deriving current travel times of the road segments based on the current
travel speeds;
indicating a shortest-time route from the starting road sub-segment to the
destination road sub-segment based on the current travel times of the road
segments.
20. A computer-readable medium having computer-executable instructions for
performing steps comprising:
obtaining current traffic data for a plurality of road segments;
displaying a road map to a user, the road map showing the plurality of road
segments;
allowing a user to individually select road segments on the road map;
displaying recent images of the currently selected road segment alongside
the road map;
showing a detail map of a particular selected road segment in response to a
command from the user, wherein the detail map includes road sub-segments
of the particular road segment;
allowing a user to individually select road sub-segments on the detail map;
displaying recent images of the currently selected road sub-segment
alongside the detail map.
21. A computer-readable medium as recited in claim 14 having further
instructions for performing an additional step of displaying a traffic
description relevant to a particular road segment when said particular
road segment is selected by the user.
22. A computer-readable medium as recited in claim 21 having further
instructions for performing an additional step of deriving the current
average speed for the particular road segment from the traffic data, the
traffic description indicating said current average speed.
23. A computer-readable medium as recited in claim 21 having further
instructions for performing an additional step of deriving the current
travel time for the particular road segment from the traffic data, the
traffic description indicating said current travel time.
24. A method of presenting traffic information comprising the following
steps:
obtaining current traffic data for a plurality of road sub-segments, the
traffic data including travel speeds for the road sub-segments;
displaying an interactive road map to a user on a graphical display
surface, the road map showing a plurality of road segments, each road
segment comprising a plurality of the road sub-segments that are
interactively selectable by is a user on the graphical display surface;
allowing a user to individually select road segments on the interactive
road map by interactively selecting road segments on the graphical display
surface;
deriving a travel time for a selected road segment from the travel speeds
of the road segment's sub-segments;
displaying the travel time for the selected road segment;
obtaining a recent image of the selected road segment;
displaying the recent image alongside the interactive road map on the
graphical display surface.
25. A computer-readable medium having computer-executable instructions for
performing the steps of claim 24.
26. A programmable device that is programmed for performing the steps of
claim 25.
27. A method as recited in claim 24, comprising an additional step of
cycling different recent images of the selected road segment when the
selected road segment remains selected.
28. A method as recited in claim 24, comprising an additional step of
cycling historical images of the selected road segment at defined
intervals.
29. A method of presenting traffic information comprising the following
steps:
obtaining current traffic data for a plurality of road sub-segments, the
traffic data including travel speeds for the road sub-segments;
displaying a road map to a user, the road map showing a plurality of road
segments, each road segment comprising a plurality of the road
sub-segments;
allowing a user to individually select road segments on the road map;
deriving a travel time for a selected road segment from the travel speeds
of the road segment's sub-segments;
displaying the travel time for the selected road segment;
obtaining a recent image of the selected road segment;
displaying the recent image alongside the road map;
showing a detail map of a particular selected road segment in response to a
command from the user, wherein the detail map includes the selected road
segment's sub-segments;
allowing a user to individually select road sub-segments on the detail map;
displaying recent images of the currently selected road sub-segments
alongside the detail map.
30. A method of presenting traffic information comprising the following
steps:
obtaining current traffic data for a plurality of road sub-segments, the
traffic data including travel speeds for the road sub-segments;
displaying a road map to a user, the road map showing a plurality of road
segments, each road segment comprising a plurality of the road
sub-segments;
allowing a user to individually select road segments on the road map;
deriving a travel time for a selected road segment from the travel speeds
of the road segment's sub-segments;
displaying the travel time for the selected road segment;
obtaining a recent image of the selected road segment;
displaying the recent image alongside the road map;
showing a detail map of a particular selected road segment in response to a
command from the user, wherein the detail map includes the selected road
segment's sub-segments;
allowing a user to select a starting road sub-segment on the detail map;
allowing a user to select a destination road sub-segment on the detail map;
deriving current travel times of the road segments based on the current
travel speeds;
indicating a shortest-time route from the starting road sub-segment to the
destination road sub-segment based on the current travel times of the road
segments.
31. A method as recited in claim 24, comprising an additional step of
displaying a traffic description relevant to a particular road segment
when said particular road segment is selected by the user, the traffic
description including the current travel time for the particular road
segment.
32. A traffic information system comprising:
a plurality of sensors indicating speeds on sub-segments of public roads;
a plurality of cameras focused on said road sub-segments;
a server computer connected and programmed to gather data from the sensors
and images from the cameras;
a plurality of client devices configured to receive sensor data and camera
images from the server computer;
a display device associated with each client device;
each client device being programmed to display an interactive road map to a
user on the display device, the interactive road map showing a plurality
of road segments, each road segment comprising a plurality of road
sub-segments that are interactively selectable by a user on the display
device;
the client device being further programmed to display recent images of the
road segments from the cameras alongside the interactive road map on the
display device in response to a user selecting such road segments.
33. A traffic information system as recited in claim 32, wherein the
cameras provide video images of said road sub-segments, the server
computer being configured to acquire still images at periodic intervals to
provide to the client devices on demand.
34. A traffic information system as recited in claim 32, wherein the
cameras provide video images of said road sub-segments, the server
computer being configured to acquire video clips at periodic intervals to
provide to the client devices on demand. |
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Claims |
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Description |
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TECHNICAL FIELD
This invention relates to public highway monitoring systems and to systems
that display the data and information available from such monitoring
systems.
BACKGROUND OF THE INVENTION
Several states have implemented systems for monitoring conditions on
potentially congested public highways. Such systems typically incorporate
sensors or speed traps installed at various locations to monitor current
traffic speeds at those locations. Often, the monitoring systems also
include video cameras at different locations to provide continuous images
and live feeds of conditions.
FIG. 1 shows a prior art traffic information system, generally designated
by reference numeral 10, for monitoring traffic on a public highway
system. Systems such as this have been implemented by several states and
other governmental agencies.
The information system of FIG. 1 includes a plurality of speed sensors or
traps 12 at various locations along a public highway or along a network of
public highways. The speed sensors might typically be spaced at intervals
ranging from a tenth of a mile in highly congested areas to perhaps over a
mile in less congested areas. Different sensors are positioned in
different directions of travel.
The information system also includes a plurality of video cameras 14. The
video cameras are positioned at chosen vantage points to allow highway
personnel to view critical stretches of highway. The cameras do not
necessarily have a one-to-one correlation with the speed sensors.
Signals from the sensors and cameras are routed to a central facility 16
for monitoring by highway personnel. The central facility typically
includes one or more computers 18 for receiving speed sensor data and for
displaying it in a meaningful way. For instance, the central facility
might have a large wallmounted map with computer-controlled lights that
flash to indicate highway locations where speeds are unusually low.
Camera video signals are routed to a video switch 20 within the central
facility and distributed to one or more monitors 22. Typically, there are
fewer monitors than available video signals, so the video switch is
programmed to cycle through the signals in a predetermined sequence.
Alternatively, the video switch might be controlled by one of computers
18. In this case, there might be some type of logic that determines which
video signal is routed to a particular monitor. For example, the computer
might be programmed to cycle through only those video signals that
correspond to highway locations that are experiencing congestion.
The information system also includes a database 24 maintained by computers
18. The database is used to store historical data relating to highway
conditions. In most cases, the database will not contain video, but
instead will contain historical speed data.
Public highway monitoring systems are used by both highway personnel and
news media. In addition, many systems are now being used to provide
realtime traffic information to the public via the Internet. For example,
traffic conditions can currently be accessed through the Internet for the
following areas at the indicated Internet sites (designated by their
uniform resource locators or URLS):
Houston "http://herman.tamu.edu/houston-real.html"
San Diego "http://www.scubed.com/caltrans/sd/bit.sub.-- map.html"
Los Angeles "http://www.scubed.com/caltrans/la/la.sub.-- transnet.html"
Manitoba: "http://umtig.mgmt.umanitoba.ca/default.htm"
Seattle: "http://www.ivhs.washington.edu/trafnet/"
To implement these sites, a server computer 26 is either located at the
central facility 16 or connected for high-speed communications with the
central facility. The server computer has a connection to the Internet.
The server computer is connected to access sensor data from the traffic
information system. It uses the sensor data to create a
continuously-updated map that indicates current traffic conditions.
While these Internet sites are useful, improvements are needed. One problem
with the sites is that they display traffic information in different ways
and require different user instructions to provide traffic information.
While it would be desirable to create a common user interface that would
access and display data from all of the available public highway
monitoring systems, this is difficult because the data from the various
systems is available only in different formats, depending on the
particular proprietary format used by each monitoring system.
Another problem lies in the fact that information is presented in visual
formats that are not immediately useful to users. For example, typical
user interfaces for traffic monitoring systems show rough maps having
roads that are divided into sections corresponding to locations of speed
sensors. The sections are color-coded to indicate current speeds measured
by corresponding sensors. For example, red might indicate "stop-and-go"
conditions, yellow might indicate "slow" conditions, and green might
indicate "normal" conditions. Icons might be used to indicate traffic
incidents such as construction zones and crashes. While such user
interfaces indeed present the available information, they do not do so in
a way that is particularly useful to a person planning a commute across
town.
SUMMARY OF THE INVENTION
The invention includes features that make traffic data more useful and
accessible to travelers and specifically to commuters. A traffic
information system in accordance with the invention has a user interface
that includes an interactive road map. The road map is a stylized
representation of a given coverage area, with major highways broken into
high-level segments such as segments between major highway intersections.
A user can interactively select any particular segment. In response, the
user interface displays either the average speed for that segment or the
time required to traverse that segment in light of the current average
speed. The user can zoom in on a particular segment, resulting in a detail
map showing a road segment broken into sub-segments. Each sub-segment is a
major highway span such as one between two significant highway
interchanges.
The traffic information system also acquires and displays still images of
whatever segment or sub-segment is currently highlighted. The still images
are acquired from video cameras located at vantage points above or
adjacent highways.
The invention allows the user to personalize the parameters of the system
to his or her specific household preferences by implementing a trip
planner. The trip planner allows a user to designate beginning and ending
locations and in response determines the best route and alternate routes
from the beginning location to the ending location. To accomplish this,
the trip planner evaluates all possible routes between two locations and
identifies the one having the shortest travel time based on current
average speeds for the sub-segments covered by the routes.
The invention further includes facilities for converting raw data and media
feeds obtained from an existing public highway monitoring system into
standard file formats used for internet enhanced personal computers and
for interactive set-top boxes so that a single user interface can utilize
data from many different highway monitoring systems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a prior art public highway monitoring system.
FIG. 2 is a block diagram of a traffic information system in accordance
with one embodiment of the invention.
FIG. 3 shows how a video server acquires still images from a plurality of
video cameras used in a public highway monitoring system.
FIGS. 4-8 shows examples of a user interface in accordance with the
invention.
FIG. 9 illustrates a common data format for providing traffic data.
DETAILED DESCRIPTION
FIG. 2 shows a traffic information system in accordance with one embodiment
of the invention, generally designated by reference numeral 30. Traffic
information system 30 utilizes or includes a plurality of public highway
monitoring systems 32 such as system 10 described above with reference to
FIG. 1. Each monitoring system includes a plurality of sensors (shown in
FIG. 1) indicating speeds on sub-segments of public roads, and a plurality
of cameras (also shown in FIG. 1) focused on the road sub-segments,
providing video images of said road sub-segments.
The traffic information system further includes a server computer 38 in
each monitoring system 32. Server computer 38 is connected and programmed
to obtain traffic data and road images from the public highway monitoring
system in the format that is used by the monitoring system, to convert it
into a pre-defined common format that is independent of the format of the
highway monitoring system, and to provide it to requesting client devices
in the common format on demand or in broadcast data form.
Server computer 38 can be one of the computers of the public highway
monitoring system shown in FIG. 1. However, it is more likely that
additional computers and servers will be used as intermediaries between
the highway monitoring system and the client devices. For example, the
server computer might be an Internet server. Alternatively, it might be
part of a headend for a cable television network that implements some form
of interactive services to subscribers. In some cases, the functions of
server 38 might be performed by more than one computer. In other cases, a
single computer might be used as a server for a plurality of highway
monitoring systems. The server computers might be located at the central
facilities of highway monitoring systems or at other, remote locations.
To provide images to server computer 38, a video server 39 is used within
or in conjunction with each monitoring system 32. The video server
maintains connections with the video cameras and captures still images or
short video clips from the cameras' video feeds at periodic intervals. The
still images are stored in bitmap, JPEG, MPEG, or other conventional
formats and provided to server computer 38 as requested.
FIG. 3 shows how a video server might be connected to acquire data and
still images from the highway monitoring system. FIG. 3 shows a video
server 39 connected to control an analog video switch 40. Switch 40
receives video signals from the cameras of the highway monitoring system,
and produces a single output to video server 39 with a signal from a
selected camera as commanded by server 39. Video server 39 has a
digitizing card that grabs still images or short motion video clips from
the supplied video signal at appropriate times. Video server 39 stores the
images as bitmaps, JPEG, or MPEG files.
Upon receiving a static image in the form of a bitmap, server computer 38
adds a time-stamp in the lower area of the image and compresses the image.
Other optional formatting, assembly and image enhancement can be performed
at this point if desired. In some systems, the highway monitoring system
will have already stamped the image with information identifying the
camera from which the still image was acquired. A short motion video clip
can be substituted for a still image if the appropriate transmission
bandwidth is available.
Server computer 38 maintains a dynamic library 41 (FIG. 2) of acquired
images stored as data files. It uses a reverse alphabetical naming
convention for the files. The first file ever generated is ZZZZZZZZ.i**
(where ** is replaced by a number representing the camera from which an
image was taken) and subsequent files are named using the alphabetically
closest but preceding name in all upper-case letters. Thus, the second
file would be ZZZZZZZY.i**, the twenty-seventh file would be ZZZZZZYZ.i**,
and so on. This naming convention can be extended by adding more
characters to the naming system, such as lower-case characters. However,
the convention described will accommodate 2.1*10.sup.11 images, thereby
accommodating one acquired image every 1.5 minutes for 610,000 years.
After acquiring each image, the server computer determines how many
converted files currently exist within library 41. If the number of images
has reached a specified limit, the oldest image is eliminated, and the
newly-acquired image is stored. This allows external devices to access a
significant historical record of transportation conditions.
Traffic information system 30 further includes a plurality of client
devices 42 configured to receive sensor data and static camera images from
the server computers. Preferably, the requesting client devices receive
data in a data format that is independent of the particular format used
within the central facilities of the public highway monitoring systems.
Client devices 42 might comprise a number of different types of devices,
each having some form of associated display device and graphical display
surface. A CRT is an example of such a display device. A flat-panel LCD is
another example.
In the embodiment shown, client devices 42 comprise personal or desktop
computers having data processors configured and connected to communicate
with server computer 38 through the Internet and to receive current
traffic data and images. Each such client device has one or more forms of
computer-readable storage media, including both volatile and non-volatile
memory. For example, the client devices shown in FIG. 2 have hard disks
for storing application programs. The client devices also have internal
electronic memory into which application programs are loaded for
execution.
A client device 42 might also be a so-called "network computer" --a
limited-capability computer designed specifically for navigation on the
World Wide Web of the Internet. Alternatively, client devices 42 might be
set-top boxes or intelligent televisions connected to receive data through
an entertainment medium such as a cable television network or a digital
satellite broadcast.
In the embodiment shown, the client devices run conventional Internet
"browsers" such as Microsoft's Internet Explorer.TM.. Such browsers
download and render multimedia content that is formatted in "hypertext
markup language" (HTML) or rendered by small, downloadable applications
called Applets. In this environment, server computers 38 might be
programmed to implement the most significant portions of a user interface.
Specifically, most of the intelligence for implementing the user interface
would be resident in server computers 38: the client devices would use
their browsers to simply display downloaded content and to relay user
inputs back to the server computers. The server computers would respond by
formatting new screen displays and downloading them for display on the
client computer.
In other embodiments, server computers 38 might be used primarily as
sources of data, with primary responsibility for a user interface being
placed upon the client computers. In other words, a client computer would
run an application program implementing a desired user interface, and
would retrieve raw images and data from a server computer as required. The
servers would provide the data in a common format which will be described
below.
With newer technology such as Active.TM. controls, a combination of these
approaches is conceivable. Client devices could use Internet browsers,
with a sophisticated user interface being implemented as one or more
intelligent ActiveX.TM. controls. The controls could be configured to
download raw data and image s rather than full HTM documents. Thus, the
intelligence behind the user interface could be distributed between the
servers and the clients in different ways.
FIGS. 4 through 8 illustrate a preferred user interface in accordance with
the invention, generally indicated by reference numeral 60. As mentioned,
the user interface can be implemented using various technologies and
different devices, depending on the preferences of the designer and the
particular efficiencies desired for a given situation.
User interface 60 includes a road map in an interactive, graphical format.
The road map is designated by reference numeral 62 in FIG. 4. In this
example, it is a stylized representation of freeways in the Seattle,
Washington, area. The entire coverage area is broken up into high-level
regions, referred t o as segments, which represent major highway
segments--such as segments between major highway intersections. These
segments are further broken into sub-segments of lengths that retain some
realistic meaning to a user. For instance, a sub-segment might be a
highway span between two well-used exits. There may or may not be a
one-to-one relationship between monitoring sensor s and highway
sub-segments: the sub-segments are defined based upon factors that have
meaning to users, rather than on the arbitrary placement of sensors. Each
sub-segment might span a plurality of sensors and have a plurality of
cameras.
FIG. 4 shows road map 62 in broad view, in which road segments are
identifiable. A user can interactively select particular road segments by
moving an on-screen cursor or other type of on-screen indicator. Towns or
residential areas are identified on the road map, as are highway numbers
and prominent geographic features. The road map is located at the left
side of the user interface.
A road image area 64 occupies the upper right portion of the user
interface. The road image area changes as the user highlights or selects
different road segments, to show recent still images or short video clips
of any currently selected road segment. The images are obtained from
server computer 38. Generally, the images come from cameras that coincide
with sub-segments of the particular segment that the user has selected.
A command area 66 occupies the lower right portion of the screen. The
command area has icons that can be selected to carry out various commands
as will be described in more detail below. The command area also has room
for logos or other advertising materials.
Referring again to road map 62, individual road segments are highlighted by
moving cursor control keys on a keyboard or infrared remote control
device, or by manipulating a mouse. The currently selected road segment is
indicated by a series of adjacent arrows or arrow heads 67. The arrows are
positioned on both sides of the segments to indicate direction of traffic.
In FIG. 4, a road segment through Renton, identified by reference numeral
68, is highlighted.
A traffic description is depicted on the user interface when a particular
road segment is highlighted or selected. The traffic description is
relevant to the selected road segment, and is positioned adjacent the road
segment when the road segment is highlighted. In FIG. 4, the traffic
description, indicated by reference numeral 70, indicates the current
average speed for the selected road segment in both directions of travel.
By selecting or activating the "time" icon in the command area, indicated
by reference numeral 72, a user can instruct the user interface to display
the current travel time for the selected road segment. The travel time is
the time, displayed in minutes and seconds, required to traverse the road
segment, based on the length of the segment and the current average speed.
Speeds and travel times are shown for both directions of travel for any
selected road segment.
FIG. 5 shows the effect of pressing an "up" key or of moving a cursor
upward and selecting road segment 76. The highlighting arrows move
upwardly to be positioned adjacent segment 76. The traffic descriptions
change to show the current speed or travel time for the new road segment,
and the image in road image area 64 changes to show a still image from the
currently selected road segment. Pressing an "up" key again highlights
road segment 78, as shown in FIG. 6, with similar changes in the traffic
description and road image area.
In general, each road segment represented on map 62 contains a plurality of
sensors and a plurality of cameras. Readings from the sensors are averaged
to derive an average speed for the overall road segment. When a particular
road segment remains selected, camera images are cycled at a rate of about
once every ten seconds, to show different recent images of the road
segment, taken from different vantage points. Optionally, the user
interface might include a way for the user to request historical images.
The user interface in this case responds by cycling historical images of
the selected road segment in the road image area at defined intervals.
FIG. 7 shows a detail map that "zooms in" on a selected road segment. The
user can select this view by highlighting the road segment and then
pressing an "action" or similar key. In a Microsoft Windows.RTM.
environment, the segment might be selected by double-clicking. A detail
map corresponds to a particular road segment and breaks that segment into
its sub-segments, designated by reference numeral 80 in FIG. 7. The user
can select individual sub-segments, in a manner identical to that already
described with reference to FIGS. 4-6. The road image area changes as
different sub-segments are selected so that a still image from the
currently selected sub-segment is always shown. If more than one camera
has coverage of the selected sub-segment, still images are cycled through
each available camera view. A progression feature is optionally
implemented in this view: after a certain sub-segment has been highlighted
for a pre-determined time, the highlight will automatically progress to
another sub-segment.
The traffic information system also includes a trip planner implemented
within the user interface. A trip planning mode can be initiated by
selecting an on-screen "commute" button 73. In response, the user is
prompted for a starting location and a destination location on the
displayed road map 62. The starting and destination locations are
specified by highlighting the desired points with directional keys and/or
mouse movement. The trip planner is configured to store two sets of
starting and destination locations, so that a user can specify and store
two different commutes. In the preferred embodiment, the selections are
made from detail maps such as the one shown in FIG. 7. This allows the
user to specify the starting and destination locations in terms of
sub-segments, thereby allowing the commutes to be tailored more carefully
to the actual trip routes used by individual users.
In response to specifying starting and destination locations in the trip
planning mode, the user interface calculates or derives a shortest-time
route from the starting location to the destination location based on
current sensor data from the highway monitoring system sensors. It
examines all possible routes, and plots or highlights the shortest-time
route on road map 62 as shown by the highlighted portion 85 in FIG. 8. A
dialog box 82 also appears, showing the estimated travel time and average
speed based on current conditions. The selected starting and destination
locations are indicated by labels 83 and 84, respectively. The user can
select either of the two stored commutes when initiating the trip planning
mode.
The shortest route for the selected commute is determined by summing the
travel times for all the segments or sub-segments of the routes.
Optionally, the trip planner allows the user to also show less preferred
routes, such as the second shortest route, the third shortest route, and
so on.
As another optional feature, the user interface is configured to
automatically show trip preview images. Specifically, images taken from
segments and/or sub segments of the preferred route are chosen and shown
in sequence in road image area 64.
As mentioned above, the server computers supply traffic data and images in
a common format that is independent of the particular formats used within
the various monitoring systems. In the embodiment described above, the
information is supplied in HTML format. However, embodiments in which the
client devices assume more responsibility for the user interface might
provide the information to the clients in a more basic format or as an
applet.
FIG. 9 illustrates a format that is advantageous in environments where
traffic data is supplied from a server without graphical formatting. In
general, the data includes a first series of values in a known order,
indicating speeds for sub-regions of a public highway system, followed by
a second series of values in a known order indicating location | | |
