Team # 56731 Page 28 of 22
£¨2£© Design traffic composition and proportion
Figure 5.3 Traffic composition and vehicle velocity distribution
£¨3£© Other important description
We totally did two simulations, and you can find details in the table below:
Table 5.1 Simulation content
Simulation times Tollbooth pattern Main street Toll lane ETC ETC lane position The first simulation Traditional Honeycomb Tollbooth Tollbooths 3 3 8 8 2 2 Bottom Road The center two lanes The second Simulation Traditional Honeycomb Tollbooth Tollbooths 3 3 8 8 0 0 0 0
Q: Why only consider ETC and artificial charges in the simulation, but do not consider the
exact-change toll pattern£¿
A: According to the literature [17], the capacity of tollbooths in the United States, MTC (Only pre-sale tickets) 500veh/h, exact-change toll(Collect some coins) 500veh/h. This time only to simulate the above situation, if we consider all the charge pattern, our model will be too complicated. You can find section 5.2 for details.
Q: Why not consider autonomous vehicles?
A: Because autonomous vehicles don¡¯t need driver. The main solution is to install an ETC device on an automatic car. Ignoring the difference in this simulation, the specific impact of autonomous vehicles on the tollbooth is described in section 4.5.
Q: How to explain the great difference between the result of the queueing model and the result of the VISSIM simulation?
A: VISSIM software has taken a lot of factors into consideration. Therefore, compared with the pure theoretical derivation, VISSIM is more practical.
Q: How to explain the great change at the traffic flow 2000veh/h.
A: Both two kinds of toll station have their maximum capacity. Therefore, there will be a great change for the total time cost and the time delayed. We can't eliminate the error between VISSUM and the reality, however, this won't affect our analysis.
5.1.2 Simulation Conclusion
(1) Sensitivity Analysis of Traffic Flow in Honeycomb Tollbooths
According to Fig. 1, Compared with the traditional tollbooth, honeycomb tollbooth is not sensitive to the traffic flow and has strong robustness. It is suitable for practical construction.
Simulation results show that the average transit time remains at about 11 seconds under different throughputs from 0 to 2000 (Unit: veh / h). We can infer that this model is not sensitive to traffic flow variations and has strong robustness which is suitable for practical construction.
Team # 56731 Page 29 of 22
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Team # 56731 Page 16 of 22
Figure 5.4 Traffic capacity changed with traffic flow Table 5.2 Honeycomb Tollbooths(All ETC)
Traffic flow (veh/h) Average time(s)
500 10.778 1000 10.900 2000 11.500 2100 11.567 2200 20.133 2500 22.878 3000 23.444 Car number (veh)
42.778 88.222 180.111 189.556 173.778 184.556 177.000 Delay time(s)
0.056 0.144 0.633 0.667 9.256 12.033 12.578 Stop time(s) 0.000 0.000 0.000 0.000 2.700 3.933 4.522
Stop number
0.000 0.000 0.006 0.001 0.541 0.621 0.723 Table 5.3 Traditional tollbooth(All ETC)
Traffic flow (veh/h) 500 1000 2000 2100 2200 2500 3000 Average time(s)
10.078 10.200 12.078 13.267 47.178 51.222 57.100 Car number
(veh) 43.000 88.444 174.556 179.667 146.889 145.000 151.333 Delay time(s)
0.056 0.100 1.911 3.078 36.422 40.444 46.933 Stop time(s)
0.000 0.000 0.767 1.378 22.567 24.367 30.878 Stop number
0.000 0.000 0.173 0.283 1.944 2.331 2.201
£¨2£©When the toll station is all configured ETC, we can get:
¢ÙThe throughput of the two toll stations is almost the same in light traffic.
¢ÚHoneycomb tollbooth is better than traditional tollbooth in heavy traffic, when traffic flow is 2500veh/h. The VISSIM simulation results show that the honeycomb tollbooth is 55% larger than the traditional tollbooth on total time cost, and about 70% on time delay.
¢ÛThe simulation results are in good agreement with the results of queuing theory.
It is shown that the queuing theory model is very reasonable to measure the throughput of the honeycomb tollbooth.
£¨2£©Two ETC and six MTC, we can get:
¢ÙThe throughput of the two toll stations is almost the same in light traffic(<400veh/h) ¢ÚThe traffic capacity of honeycomb tollbooths will decrease in heavy traffic(>900veh/h). ¢ÛThe traffic flow between 400 veh/h and 900 veh/h honeycomb tollbooths is stronger than the traditional tollbooth.
Team # 56731 Page 17 of 22
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