evaluation of its applications on the køge bugt motorway, denmark
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Evaluation of ITS applications on the Køge Bugt Motorway, Denmark
Jens Toft Wendelboe
Technical ConsultantTraffic Management Department
Danish Road Directorate
Contents of presentation
• Background
• ITS applications used on the Køge Bugt Motorway
• Evaluation – aspects regarding traffic and technical performance
Widening of the Køge Bugt Motorway
Køge Bugt Motorway: 2002 - 2003
Issues and applications
Issues leading to implementation of ITS • Safety• Traffic flow
Selected ITS applications• Dynamic speed limits• Dynamic route guidance• Traffic monitoring
Dynamic speed limits and traffic monitoring
Dynamic route guidance
Display near Greve
Evaluation purposes
• To investigate drivers reactions and satisfaction
• To examine technical performance
• To gain experience with ITS applications to be used in future projects
SurveysDynamic speed limits • Do drivers comply with displayed speed limits?• Does the system provide more uniform speeds?• Does the system provide a more uniform flow?• Do the displays change as specified?
Dynamic route guidance • Will drivers change to the least congested route?• What are the travel time reductions?• Are displayed delays in accordance with experienced delays?
Both • What do the drivers think of the applications?
Data & method
Analyses are based on• Loop detector data• System data/log files• Data obtained via questionnaire among drivers• Experiences from daily service (TIC)
Types of analyses• Before and after studies (only after studies when examining
technical performance and drivers´ opinion)
Results – dynamic speed limits• Drivers to not comply with displayed speed limits unless traffic
conditions force them to
• However, speeds are decreased by approximately 5 km/h overall
• The faster people drive, the greater the speed reduction
• Speeds have only become more uniform at places and times with heavy congestion
• The same tendency applies when it comes to traffic flow
• Important: drivers receive information about congestion ahead, and they respond to the warning: this could mean reduced risk of rear-end collisions
• There have been problems with errors in displayed speed limits towards Copenhagen
• Only few errors in displayed speed limits towards Køge
• Problems with errors in both directions in extreme situations (accidents)
Day Duration % of rush hour Duration % of rush hourMon 9/9-02 00:21:57 12,2 00:00:00 0,0
Tue 10/9-02 00:32:31 18,1 00:00:00 0,0Wed 11/9-02 00:00:00 0,0 00:00:00 0,0Thu 12/9-02 00:16:14 9,0 00:00:00 0,0
Fri 12/9-02 00:14:45 8,2 00:00:00 0,0
Thu 29/8-02 00:25:35 14,2 - -Wed 2/10-02 - - 00:19:01 9,1
Examples of duration of errors in displayed speed limits
6.30 - 9.30 a.m.Towards Copenhagen
2.30 - 6.00 p.m.Towards Køge
Results – dynamic route guidance
• Drivers do not change route unless there is a considerable difference in the displayed delays – special days
• Up to 14% of the traffic has been redistributed in cases of major differences in displayed delays
• Displayed delays often varies significantly from experienced delays
• Drivers find it difficult to understand the displayed information
• Due to unforeseen variations, there have been no travel time reductions in general
3_5_Nord: 2/12-02
0
2
4
6
8
10
06:3
0
06:4
5
07:0
0
07:1
5
07:3
0
07:4
5
08:0
0
08:1
5
08:3
0
08:4
5
09:0
0
09:1
5
09:3
0
Time
Min
utes
Smoothed delay Actual delay
Questionnaire – main results2.500 postcards were distributed and the return rate was app. 25%
• App. every second driver feels safer with dynamic speed limits• App. every second driver is indifferent• App. 4% feels less safe
Drivers are having trouble understanding displayed delays, due to:• Lack of knowledge regarding route numbers• Displayed information is too complicated• Too much information on the displays• Display/letters are too small
68% of the drivers: the difference in displayed delays has to be 5 minutes or more, otherwise they will stay on the route first chosen
Comments reveal that a lot of drivers think that the displayed information/speed limits rarely correspond with actual conditions
Never the less, more than 80% of the drivers were favourably disposed to the ITS applications
Overall assessment
Conditional success:
• Applications function, but not always
• Applications affect drivers, but not sufficiently
• Applications are likely to produce better results if technical performance is improved
Thank you for your attention!
Any questions?
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