An evaluation of vehicle deceleration profiles
TL;DR: In this article, the first vehicles to stop at signalized intersections were examined for the purpose of evaluating the validity of the common assumption of constant and uniform deceleration rates, and the analysis of the field observations indicated that 69% of the vehicles demonstrated decelerations associated with non-uniform rates.
Abstract: Vehicles stopping at signalized intersections were examined for the purpose of evaluating the validity of the common assumption of constant and uniform deceleration rates. The data set consisted of the first vehicles to stop upon the onset of the yellow signal interval with measurements of the initial approach speed, deceleration time, and deceleration distance. The deceleration rate may be computed using only two of the three measured values; thus the rate for each vehicle can be determined by three differnt equations. With nonuniform deceleration profiles, the equations will produce different values; and the degree of nonuniformity can be determined by comparing the differences in the computed deceleration rates. The analysis of the field observations indicated that 69% of the vehicles demonstrated deceleration profiles associated with nonuniform deceleration rates. Furthermore, the deceleration profile and the degree of nonuniformity were found to be a function of the initial approach speed.
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TL;DR: In this article, the authors analyzed the deceleration behavior of different vehicle types (car, car, motorized two and three-wheeler) on the Nagpur-Mumbai Express Highway at Wardha, India.
Abstract: Deceleration characteristics of vehicles are important for intersection design, deceleration lane design, traffic simulation modeling, vehicular emission and fuel consumption modeling, etc. Heterogeneous traffic stream consists of vehicles with wide variation in their physical dimensions, weight to power ratio and dynamic characteristics, which affect their deceleration behaviour. The majority of past studies are restricted to deceleration behaviour study of cars and trucks in homogeneous traffic. The present study aims to analyze the deceleration behaviour of different vehicle types (like truck, car, motorized two and three-wheeler) on Nagpur-Mumbai Express Highway at Wardha, India. Drivers were asked to decelerate their vehicles from their maximum speed to zero speed in the shortest time and their speed profiles were collected using Global Positioning System. Deceleration behaviour of different vehicle types is significantly different. Vehicles with higher maximum speed have higher deceleration time, deceleration distance, maximum and mean deceleration rates during their deceleration manoeuvre. In deceleration manoeuvres, vehicle’s deceleration rate initially increases, attains the maximum deceleration and decreases afterwards. A dual regime model is developed to describe deceleration behaviour over the entire speed range of all vehicle types except cars. For cars, a second order polynomial is proposed.
85 citations
TL;DR: The method developed in this paper uses vehicle speeds and deceleration collected using standard in situ loops and tubes, to determine conflicts using vehicle decelerations and to assess the possibility of automatic safety monitoring at Pelican crossings.
65 citations
TL;DR: In this article, the normal deceleration behavior of current passenger vehicles is evaluated at stop sign-controlled intersections on urban streets on the basis of in-vehicle Global Positioning System data.
Abstract: Deceleration characteristics of passenger cars are often used in traffic simulation, vehicle fuel consumption and emissions models, and intersection and deceleration-lane design. Most previous studies collected spot speed data with detectors or radar guns. Because of the limitations of the data collection methods, these studies could not determine when and where drivers began to decelerate. Therefore, the studies may not provide an accurate estimation of deceleration time and distance. Furthermore, most previous studies are based on outdated and limited data, and their conclusions may not be applicable to the current vehicle fleet and drivers. The normal deceleration behavior of current passenger vehicles is evaluated at stop sign-controlled intersections on urban streets on the basis of in-vehicle Global Positioning System data. This study determined that drivers with higher approach speeds decelerated over a longer time and distance. Higher initial deceleration rates were also associated with higher app...
47 citations
TL;DR: The results of this study suggest that a combination of auditory and visual alerts may be effective at improving older drivers’ glance behavior while making left turns at intersections.
Abstract: Older drivers are known to make significantly fewer glances toward hazards that are hidden from view (latent hazards) than middle-aged drivers. This is especially true when the driver is making a l...
14 citations
Cites background from "An evaluation of vehicle decelerati..."
...If a vehicle is traveling 30mph (44 ft/s) and the vehicle is decelerating at 10 ft/ s—a value typical of decelerations found at intersections (27)—then the stopping time is 4....
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01 Aug 1998
TL;DR: In this paper, the authors developed an analytical model to estimate fuel consumption and investigate the effects of signal timing on fuel consumption, and the results from these experiments indicate that total fuel consumption with respect to signal cycle time possesses a convex pattern.
Abstract: The objectives of this report are to develop an analytical model to estimate fuel consumption and to investigate the effects of signal timing on fuel consumption. Several numerical experiments, including a variety of geometric configurations, traffic conditions, and signal timing are conducted to test the AFCM estimation capability and to investigate the effects of signal timing on fuel consumption. The results from these experiments indicate that total fuel consumption, with respect to signal cycle time, possesses a convex pattern. In order to analytically establish the relationship between fuel consumption and signal timing, a three-term form is reduced from the AFCM to represent major effects of vehicle characteristics, traffic behavior, and fuel consumption parameters on optimal cycle length. The first term represents vehicle ideal fuel consumption, the second term describes vehicle fuel consumption during acceleration after a stop, and the third term accounts for stochastic effects. Numerical analysis and comparisons show that the optimal cycle lengths from the expression are rather close to those from the AFCM.
10 citations
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TL;DR: Criteria are presented for the design of amber signal light phases through whose use such “dilemma zones” can be avoided, in the interest of over-all safety at intersections.
Abstract: A theoretical analysis and observations of the behavior of motorists confronted by an amber signal light are presented. A discussion is given of the following problem when confronted with an improperly timed amber light phase a motorist may find himself, at the moment the amber phase commences, in the predicament of being too close to the intersection to stop safely or comfortably and yet too far from it to pass completely through the intersection before the red signal commences. The influence on this problem of the speed of approach to the intersection is analyzed. Criteria are presented for the design of amber signal light phases through whose use such “dilemma zones” can be avoided, in the interest of over-all safety at intersections.
298 citations
TL;DR: The polynomial model has been found to be the best overall for predicting acceleration distance and fuel consumption and similar results have been found for deceleration profiles.
Abstract: Three new models of acceleration profile (a two-term sinusoidal, a three-term sinusoidal, and a polynomial model) are described. These models yield the S-shaped speed-time trace indicated by data from driving in real-life traffic conditions, satisfy the realistic conditions of zero jerk (except the two-term sinusoidal model) and zero acceleration at the start and end of the acceleration, and allow for the position and the value of the maximum acceleration to vary for a given average acceleration rate. A comparative evaluation of these three models and the previously known constant and linear-decreasing acceleration models is reported. The evaluation criteria are distance traveled and fuel consumed during acceleration. The performances of the five models are compared under three sets of conditions: acceleration time and distance known, time known but distance unknown, and both time and distance unknown. The comparisons are made separately for central business district (CBD), other urban and nonurban traffi...
126 citations
Journal Article•
TL;DR: In this paper, improved design procedures are described for deceleration rate, effect of grades, approach speed and cross-flow time deduction, which are dealt with in this paper.
Abstract: Improved design procedures are described. Subjects dealt with include deceleration rate, effect of grades, approach speed and cross-flow time deduction.
5 citations