Safety

Second-Order Time to Collision With Non-Static Acceleration

Matin, Hossein Nick Zinat
Yeo, Yuneil
Ngo, Amelie Ju-Kang
Paiva, Antonio R.
Utke, Jean
Maria Laura Delle Monache
2025

We propose a second-order time to collision (TTC) considering non-static acceleration and turning with realistic assumptions. This is equivalent to considering that the steering wheel is held at a fixed angle with constant pressure on the gas or brake pedal and matches the well-known bicycle model. Past works that use acceleration to compute TTC consider only longitudinally aligned acceleration. We additionally develop and present the Second-Order Time-to-Collision Algorithm using Region-based search (STAR) to efficiently compute the proposed second-order TTC and overcome the current...

Dynamic Risk Assessment for Autonomous Vehicles from Spatio-temporal Probabilistic Occupancy Heatmaps

Wang, Han
Yeo, Yuneil
Paiva, Antonio R.
Goodman, Jack P.
Utke, Jean
Maria Laura Delle Monache
2025

Accurately assessing collision risk in dynamic traffic scenarios is a crucial requirement for trajectory planning in autonomous vehicles (AVs) and enables a comprehensive safety evaluation of automated driving systems. To that end, this paper presents a novel probabilistic occupancy risk assessment (PORA) metric. It uses spatiotemporal heatmaps as probabilistic occupancy predictions of surrounding traffic participants and estimates the risk of a collision along an AV’s planned trajectory based on potential vehicle interactions. The use of probabilistic occupancy allows PORA to account for...

A Method for Design and Specification of Longitudinal Controllers for Vehicle Automation

Godbole, Datta N.
Raja Sengupta
1998

Within the context of advanced vehicle control systems, the authors present a general methodology for the design and evaluation of vehicle safety systems. The safety of a vehicle automation system is characterized by the operating region and capabilities of the controller, and the disturbance generating capabilities of the traffic and roadway. The authors illustrate the methodology with reference to a vehicle following scenario. Different information structures are compared by analyzing their effect on safety and system capacity

Capacity Analysis of Traffic Flow Over a Single-Lane Automated Highway System⋆

Michael, James B
Godbole, Datta N
Lygeros, John
Raja Sengupta
1998

We calculate bounds on per-lane Automated Highway System (AHS) capacity as a function of vehicle capabilities and control system information structure. We assume that the AHS lane is dedicated for use by fully automated vehicles. Capacity is constrained by the minimum inter-vehicle separation necessary for safe operation. A methodology for deriving the safe minimum inter-vehicle separation for a particular safety criterion is presented. The inter-vehicle separation, which depends on the vehicle braking capability, control loop delays and operating speed, is then used to compute site-...

Safety and Capacity Analysis of Automated and Manual Highway Systems

Carbaugh, Jason
Godbole, Datta N.
Raja Sengupta
1998

This paper compares safety of automated and manual highway systems with respect to resulting rear-end collision frequency and severity. Safety is related to driver, vehicle and highway operating characteristics. Our safety analysis method maps the variation in these operating characteristics, modeled by probability distributions, to the probability and severity of the first rear-end crash due to a hard braking disturbance on the highway. The results show that automated driving is safer than the most alert manual drivers, at similar speeds and capacities. We also present a detailed safety-...

Safety and Capacity Analysis of Automated and Manual Highway Systems

Carbaugh, Jason
Godbole, Datta N.
Raja Sengupta
1999

This paper compares safety of automated and manual highway systems with respect to result- ing rear-end collision frequency and severity. The results show that automated driving is safer than the most alert manual drivers, at similar speeds and capacities. We also present a detailed safety-capacity tradeo study for four di erent Automated Highway System concepts that di er in their information structure and separation policy.

Ad-Hoc Medium Access Control Protocol Design and Analysis for Vehicle Safety Communications

Raja Sengupta
Xu, Qing
Mak, Tony
Ko, Jeff
2004

This paper studies the design of ad-hoc Medium Access Control (MAC) protocols for a vehicle or the roadside to send safety messages to other vehicles. Such a protocol is needed by Advanced Vehicle Safety Systems (AVSS) and the national Dedicated Short Range Communications (DSRC) architecture. The problem is formulated to meet the communication requirements of vehicle safety applications and the DSRC multi-channel operation model. We propose several ah-hoc protocols, all based on the principles of repetition coding. Analytical bounds of the protocols' performance are derived. Simulations...

WTRP - Wireless Token Ring Protocol

Ergen, M.
Lee, Duke
Raja Sengupta
Varaiya, P.
2004

The wireless token ring protocol (WTRP) is a novel medium access control (MAC) protocol for wireless local area networks (WLANs). In contrast with IEEE 802.11 networks, WTRP guarantees quality of service (QoS) in terms of bounded latency and reserved bandwidth, which are critical in many real-time applications. Compared to 802.11, WTRP improves efficiency by reducing the number of retransmissions due to collisions, and it is more fair as all stations use the channel for the same amount of time. Stations take turns transmitting and give up the right to transmit after a specified amount of...

Vehicle-to-Vehicle Safety Messaging in DSRC

Xu, Qing
Mak, Tony
Ko, Jeff
Raja Sengupta
2004

This paper studies the design of layer-2 protocols for a vehicle to send safety messages to other vehicles. The target is to send vehicle safety messages with high reliability and low delay. The communication is one-to-many, local, and geo-significant. The vehicular communication network is ad-hoc, highly mobile, and with large numbers of contending nodes. The messages are very short, have a brief useful lifetime, but must be received with high probability. For this environment, this paper explores the efficacy of rapid repetition of broadcast messages. This paper proposes several random...

A Multi-channel VANET Providing Concurrent Safety and Commercial Services

Mak, Tony K.
Laberteaux, Kenneth P.
Raja Sengupta
2005

One of the key goals of a vehicular ad-hoc network (VANET) is providing sufficient quality of service (QoS) for real-time safety applications while concurrently supporting commercial services. This paper proposes a multi-channel wireless communication architecture and protocol for the scenario where commercial services are provided by roadside infrastructure. This solution extends the IEEE 802.11 wireless LAN protocol to schedule periodic safety messages in a "safety channel". It explicitly supports concurrent non-time-critical communications in separate, non-safety "service channels"....