1. The phenomenon of high-speed-car-following on Chinese highways Mingmin Guo, Zheng Wu Department of Mechanics and Engineering Science Fudan University

2. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-2 Outline  Background and motivation  Data Sets  Results and analysis  Conclusions

3. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-3 Background and motivation  Traffic flow is of complicated nonlinearity: stop-and- go phenomenon under high density.  We found the nonlinearity under low density on urban expressways: high-speed-car-following (HSCF).

4. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-4 Background and motivation  Similar results in literatures German highway A1, loop detector data Neubert et al., PRE 1999, 60(6) : 6480-6490 U.S. highway 101, NGSIM data Chen et al., IEEE Trans. Intell. Transp. 2010: 11(4) : 773-785

5. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-5 Background and motivation  Empirical observations play crucial roles.  Numerous important achievements  Next Generation Simulation (NGSIM) project  The traffic videos taken from the intercity highways are lacking.  So we studied the HSCF phenomenon on intercity highways based on traffic videos.

6. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-6 Outline  Background and motivation  Data Sets  Results and analysis  Conclusions

7. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-7 Data Sets  100 hours of traffic video from fours locations

8. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-8 Data Sets  Seven samples from 17.5 hours out of total videos  About 40,000 vehicles  94392 speed data 、 28201 space headway data

9. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-9 Data Sets  The vehicle class was collected.  The proportions of heavy vehicles of two frequently- used NGSIM data  I-80 (Berkeley Highway) : 2.2%  US-101 (Hollywood Freeway) : 3.8%

10. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-10 Data Sets  Overview of the traffic situation

11. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-11 Outline  Background and motivation  Data Sets  Results and analysis  Conclusions

12. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-12 Results and analysis  Time headway (h t ): the time difference between two successive vehicles passing the same location.  In this paper, it was calculated by where h s is space headway, v is speed.

13. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-13 Results and analysis  The percentages of h t ≤ 2 s and h t ≤ 1 s are remarkable.

14. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-14 Results and analysis  The small h t are related to the driving behavior with high speed and small spacing, so-called “high-speed- car-following”. Frequency distribution of the data with h t ≤1 s in sample 3 for different speed ranges

15. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-15 Results and analysis  The distributions of HSCF vehicles on each lane are different. Proportion of the vehicles with h t ≤1 s in sample 3 for each lane  Most of the HSCF vehicles are cars.

16. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-16 Results and analysis  Dependence of the average speed at different lanes on the number of HSCF vehicles----in 1 min interval Sample 3, G2 Sample 5, G15w

17. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-17 Results and analysis  Dependence of the flow at different lanes on the number of HSCF vehicles----in 1 min interval Sample 3, G2 Sample 5, G15w

18. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-18 Results and analysis  Dependence of the density at different lanes on the number of HSCF vehicles----in 1 min interval Sample 3, G2 Sample 5, G15w

19. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-19 Results and analysis  HSCF can roughly be classified into two types: Active HSCF Passive HSCF

20. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-20 Results and analysis  HSCF often makes the rear vehicle’s driver take a lane-changing maneuver as well.

21. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-21 Results and analysis  Dependence of the average frequency of lane- changing at different lanes on the number of HSCF vehicles----in 1 min interval

22. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-22 Outline  Background and motivation  Data Sets  Results and analysis  Conclusions

23. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-23 Conclusions  HSCF, such a dangerous driving behavior, has a relatively high frequency of occurrence on Chinese intercity highways.  Cars, fast lanes and locations near the urban area have higher proportion of HSCF than trucks, slow lanes and locations far from the urban area, respectively.

24. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-24 Conclusions  In general, the flow and the density will increase as the frequency of HSCF increases. HSCF may affect the capacity and level of service.  As the frequency of HSCF increases, the average velocity of the left lane decreases, while the average velocity of the other lanes increases.

25. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways 25-25 Conclusions  HSCF can be classified into active type and passive type. The latter type is caused by lane-changing and overtaking.  HSCF may cause lane-changing as well, and the frequencies of them vary synchronously.  HSCF enhances the nonlinearity of traffic flow under low density.

26. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways

27.  In sample 3 (09:37-11:24)  258 cars with h t ≤ 1s were observed.  13 trucks with h t ≤ 1s were observed.  Among the 258 HSCF cars, only 2 of them followed trucks.  Among the 13 HSCF trucks, more than a half, i.e. 7 of them, travelled after cars. Appendix-1

28. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways Appendix-2  The time series of the flow, the density and the velocity of sample 3

29. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways Appendix-3  The fundamental diagram of sample 3----in 1 min interval

30. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways Appendix-4  The fundamental diagram of sample 3---- based on the moving average of 15-min period

31. ICNM-VI——The phenomenon of high-speed-car-following on Chinese highways Appendix-5  The trends of the flow and the HSCF----based on the moving average of 15-min period