UTC Case Study Estimates That Automatic Emergency Braking Technology Can Improve Energy Economy by up to 34.6 Percent and Reduce Pollutant Emissions by 22.5 Percent.
Researchers Assessed Environmental Impact for Automatic Emergency Braking Systems via Two Simulated Case Studies in California and Nevada.
Made Public Date
02/21/2022

415

Riverside County: California,
United States

1291

Las Vegas, Nevada,
United States
Identifier
2022-01625
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Estimating the Impacts of Automatic Emergency Braking (AEB) Technology on Traffic Energy and Emissions

Summary Information

Automatic Emergency Braking (AEB) systems can improve safety by activating the vehicle’s braking system in detection of a potential collision. This study developed a methodology to estimate and quantify potential reduction in energy consumption and tailpipe emissions due to the AEB system as a result of effectiveness in collision avoidance. The main idea of this methodology was to identify traffic accidents that can be potentially avoided by AEB systems, and predict the environmental impact of AEB systems under a “what-if” scenario (i.e., no accident). Real-world scenarios for Riverside, CA and Las Vegas, NV were studied using the proposed methodology as case studies to demonstrate the efficacy of the proposed methodology.

METHODOLOGY

A research team led by the Pacific Southwest Region University Transportation Center (UTC) developed a structured database that fused various datasets including real-world traffic state measurements, traffic accident records, roadway geometry, and weather information.

Using input data from the integrated database, two sets of traffic data were obtained: 1) a representation of normal traffic conditions without accident occurrence; and 2) the actual traffic conditions with the occurrence of accident, across a spatiotemporal region large enough to cover all of the potential impacts. After identifying the accidents’ impact region and predicting the traffic conditions under a “what-if” scenario (i.e., no accident) using machine learning techniques, the U.S. Environmental Protection Agency’s Motor Vehicular Emissions Simulator (MOVES) model was applied to conduct energy/emissions analysis. The benefit of the AEB system was estimated by calculating the difference in fuel and energy consumption and the amount of pollutants emitted in both the with and without traffic accident scenarios.

 

FINDINGS

Case I: Rear-end Collision that Occurred 5/16/2017 on SR-91 in Riverside, CA

The energy consumption within the spatiotemporal impact region would be reduced by up to 14.99 percent and the resultant pollutant emissions would decrease by as much as 17.59 percent, as shown in Table 1.

Table 1: Estimated Environmental Impact of Entire Spatiotemporal Region due to the Accident (Riverside, CA)

 

CO(g)

HC(g)

NOx(g)

PM2.5_Ele(g)

PM2.5_Org(g)

Energy(KJ)

CO2(g)

Fuel(g)

Actual (with accident)

12.14

0.117

0.55

0.008

0.04

107295.99

7633.90

2390.80

Predicted (if incident-free)

10.00

0.115

0.71

0.007

0.03

91212.48

6489.59

2032.42

Reduction (%)

17.59

1.7

-28.31

12.5

16.67

14.99

14.99

14.99

 

Case II: Rear-end Collision that Occurred 1/2/2020 on US-95 in Las Vegas, NV

The results showed that the AEB technology may improve energy economy by up to 34.6 percent and reduce pollutant emissions by as much as 22.5 percent if the selected accidents could be avoided. These results are shown in Table 2.

Table 2: Estimated Environmental Impact of Entire Spatiotemporal Region due to the Accident (Las Vegas, NV)

 

CO(g)

HC(g)

NOx(g)

PM2.5_Ele(g)

PM2.5_Org(g)

Energy(KJ)

CO2(g)

Fuel(g)

Actual (with accident)

36.92

0.31

1.14

0.024

0.11

378107.4

26901.59

8425.09

Predicted (if incident-free)

28.62

0.3

1.51

0.02

0.09

247451.1

17605.65

5513.77

Reduction (%)

22.5

4.1

-32.1

16.7

17.4

34.6

34.6

34.6

Results Type