SEIDM: A Safe and Efficient Intelligent Driver Model for Autonomous Driving Behavior
Authors: Yuyang Yao, Shaocheng Luo
Organizations: Department of Information and Communication Engineering, Tongji University, Shanghai, China · Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
The Intelligent Driver Model (IDM) is a cornerstone of Adaptive Cruise Control (ACC), valued for its interpretable parameters and effectiveness in car-following behavior modeling. However, its inherent conservatism leads to prolonged stabilization and reduced traffic efficiency, which have received limited attention. In this paper, we propose SEIDM (Safe and Efficient Intelligent Driver Model), an enhanced IDM extension designed to improve traffic flow efficiency without sacrificing safety. SEIDM introduces an adaptive safety factor to dynamically modulate the impact of the safe deceleration term in acceleration decisions. This allows vehicles to follow more assertively under safe conditions while behaving more cautiously in potential hazards. Extensive urban traffic simulations show that SEIDM achieves significantly shorter stabilization spacing and faster convergence to traffic flow equilibrium, outperforming the original IDM and its variants in traffic stability and efficiency.
Figures & tables
Fig. 1: Representation of IDM. Vehicle B continuously adjusts its acceleration based on its and Vehicle A’s motion.
Fig. 2: The illustration of follower acceleration versus inter-vehicle distance across a range of relative speeds, with corresponding TTC values shown on the right axis. In this analysis, the follower’s speed is constant at 90 km/h , while the leader’s speed varies from 85% to 100% of this value. The IDM parameters from Section V-B are used.
Fig. 3: Comparison between the stabilized following distance and the desired distance in IDM. The horizontal axis represents the ratio of the stabilized speed to the desired speed v0 . As the stabilized speed approaches v0 , the gap between the actual and desired distances increases markedly, highlighting IDM’s growing deviation from optimal spacing at higher speeds.
Fig. 4: Illustration of SEIDM behavior. Compared to IDM (solid lines), SEIDM (dashed lines) provides stronger deceleration for quicker hazard response (Vehicle B → Vehicle A) and more aggressive acceleration to reach the desired speed efficiently under safe conditions (Vehicle C → Vehicle D).
Fig. 5: Leader speed profile.
Parameter
Variable
Value
Unit
Maximum acceleration
a0
1.46
m/s2
Comfortable deceleration
b0
2.0
m/s2
Desired speed
v0
100
km/h
Limited maximum speed
vmax
95
km/h
Safe time headway
T
1.6
s
Static required distance
s0
2
m
TABLE I: IDM’s and SEIDM’s Parameter Configuration
r
0
0.05
0.1
0.2
Stabilization Spacing ( m )
102.67
100.47
98.41
94.70
Traffic Throughput ( veh/h )
925.3
945.5
965.3
1003.1
Braking Duration ( s )
31.6
29.3
26.95
25.8
Peak Deceleration ( m/s2 )
−4.05
−4.14
−4.2
−4.31
r
0.3
0.4
0.5
0.6
Stabilization Spacing ( m )
91.43
88.53
85.95
83.64
TABLE II: Results on the Selection of r
Model
Spacing ( m )
Period ( s )
Traffic Throughput ( veh/h )
Krauss-FM [ 21 ]
44.28
3.4
2145.44
IDM [ 2 ]
102.67
2472.4
925.29
Deng et al. [ 22 ]
102.67
2483.2
925.29
Derbel et al. [ 1 ]
-
-
-
Dardour et al. [ 3 ]
196.06
4490.6
484.55
SEIDM
83.64
1479.8
1135.8
TABLE III: Experimental Results in Traffic Flow Stabilization Scenario
Fig. 6: Relationship among the ego velocity, the leader velocity, and the safe velocity of a vehicle in traffic flow.
Fig. 7: Relationship between average distance and simulation time across various car-following models.
Model
Final Spacing ( m )
Spacing Reduction ( m )
IDM [ 2 ]
17.96
84.71
SEIDM
17.45
66.19
TABLE IV: Experimental Results in the Consecutive Vehicle Emergency Braking Scenario
Model
Metric
0
1
2
3
4
IDM [ 2 ]
Final Spacing ( m )
17.98
17.98
17.98
17.97
17.97
Spacing Reduction ( m )
84.69
84.69
84.69
84.70
84.70
SEIDM
Final Spacing ( m )
17.47
17.47
17.47
17.46
17.46
Spacing Reduction ( m )
66.17
66.17
66.17
66.18
66.18
Model
Metric
5
6
7
8
9
IDM [ 2 ]
Final Spacing ( m )
17.70
17.970
17.97
17.96
-
TABLE V: Experimental Results in the Traffic Flow Emergency Braking Scenario
Model
Stabilization Period ( s )
Response Time ( s )
IDM [ 2 ]
2024.2
555.9
SEIDM
1276.72
317.516
TABLE VI: Experimental Results in the Vehicle Insertion Scenario
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Yuhui Liu, Samannita Halder, Shian Wang +1
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Xiaohua Zhao, Zhaowei Huang, Chen Chen +1
Beijing Key Laboratory of Traffic Engineering, Beijing University of Technology, Beijing, 100124, P.R.China
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