Abstract
This paper aims to identify the characteristics of acceleration/deceleration (accel/decel) constraints in com-mercial adaptive cruise control (ACC) and investigate their potential impact on traffic flow. We have collected empirical accel/decel data in Massachusetts and Georgia from various ACC-equipped vehicles including Tesla Model X/3, Civic, and Prius. Unlike constant values adopted in the literature so far, the observed maximum accel/decel rates across different ACC manufactures all suggest that the accel/decel constraints decrease linearly with vehicle speeds. Based on the data we also find: i) different ACC manufacturers seem to adopt different accel/decel constraints, ii) maximum accel rates do not vary significantly with the engine mode but differ in free-motion and car-following regimes iii) maximum decel rates show a strong correlation with minimum times to collision. We further demonstrate that accel/decel constraints in the ACC can contribute to speed overshootings/undershootings, causing capacity loss in the accelerating process and deteriorating congestion in the decelerating case. To reveal the underlying mechanisms, the paper develops an ODE model to analyti-cally approximate the speed overshootings/undershootings and correlate them with the accel/decel constraints as well as ACC control parameters. Besides speed over/undershootings, simulation results also show that accel/decel constraints in ACCs can undermine the string stability.
| Original language | English |
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| Title of host publication | 2022 IEEE 25th International Conference on Intelligent Transportation Systems, ITSC 2022 |
| Publisher | Institute of Electrical and Electronics Engineers Inc. |
| Pages | 3069-3076 |
| Number of pages | 8 |
| ISBN (Electronic) | 9781665468800 |
| DOIs | |
| State | Published - 2022 |
| Event | 25th IEEE International Conference on Intelligent Transportation Systems, ITSC 2022 - Macau, China Duration: Oct 8 2022 → Oct 12 2022 |
Publication series
| Name | IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC |
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| Volume | 2022-October |
Conference
| Conference | 25th IEEE International Conference on Intelligent Transportation Systems, ITSC 2022 |
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| Country/Territory | China |
| City | Macau |
| Period | 10/8/22 → 10/12/22 |
Funding
This research was funded by NSF Awards #1932451 and #1826162. The authors would like to thank our collaborators Dr. Tienan Li and Prof. Danjue Chen from Umass Lowell for their data collection efforts.