Despite numerous theoretical models, only limited field experiments have been conducted to investigate traffic oscillation propagation, and the relationships between traffic oscillation features (e.g., period, speed variation, spacing and headway) have not received quantitative analysis. We conducted a set of field experiments designed to inspect such relationships.
The field experiments were implemented on October 24th, 2015. The experiment settings are summarized below.
Location: All experiments were carried out on a 5 km highway section of National Highway G202 (Lanxi direction) in Harbin, Heilongjiang, China. There are no traffic lights on the test road. The test road is a bi-direction and four-lane highway. Note that national highway G202 is not a freeway, and the speed limit is 80 km/h. It allows vehicles to have a U-turn on the test road. The traffic is light on the test road so that the vehicle platoon is not disturbed by other vehicles. Further, with the cooperation of traffic polices, it is safe and legal to conduct a set of traffic oscillation field experiments on the test road.
Equipment: The vehicle platoon contained 12 vehicles with identical sizes and models (i.e., Kia K5). A high-resolution GPS device, called GPS-RTK based STAR-RTK-M9, was installed in each vehicle to collect field data (i.e., locations and speed). The data measurement errors of the GPS device are within ±1m for location and ±1km/h for speed. And the sampling frequency is 20Hz (i.e., the sampling time interval is 0.05s).
Configurations: Since the objective of the field experiments was to investigate the propagation of traffic oscillation and the relationships in traffic oscillation features, we conducted 21 experiments including 12 oscillation experiments and 9 stationary experiments. Within each time period, the ideal leading vehicle speed profile would accelerate to the maximum speed with the designed acceleration rate, then cruise at the maximum speed, and finally decrease the speed to the minimum speed with a deceleration rate identical to the negation of the previous acceleration rate. Note that it is difficult for the leading vehicle driver to follow the perfect speed profile, and the driver was just asked to follow this profile as best as he/she can. Other drivers were told to follow the preceding vehicle as usual without overtaking. When approaching the end of the road segment, all GPS devices stopped collecting data, and the vehicle platoon made a U-turn and stopped. After all vehicles stopped, a new run of the experiment began, and the GPS devices restarted to collect data at the same time.
This folder contains data of both oscillation experiments and stationary experiments. Full-text of this paper is available at https://www.researchgate.net/publication/342689605_A_Study_of_Relationships_in_Traffic_Oscillation_Features_Based_on_Field_Experiments