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Finite element studies of temperature effect on braking distance
Published in Eyad Masad, Amit Bhasin, Tom Scarpas, Ilaria Menapace, Anupam Kumar, Advances in Materials and Pavement Performance Prediction, 2018
T. Tang, K. Anupam, A. Scarpas, C. Kasbergen, E.A. Masad
Braking distance is one of the basic standards for road design and maintenance practices. Skid resistance, which is represented by the skid resistance coefficient between the pavement and the tire, is the key parameter that can influence braking distance. The braking distance required for safety varies with pavement surface texture, because skid resistance varies from one surface to another. At low speeds, micro-texture is the main contribution to skid resistance, whereas at high speeds, macro-texture is the main contribution (Shafii 2009). In general, skid resistance is affected by factors related to the vehicle, pavement, and environment (Hall 2009). Even though vehicle and pavement related factors can be controlled to some extent, the environmental factors like rain and ambient temperature are impossible to be controlled. Previous research study showed that the skid resistance measured in the summer season is usually lower than the winter one regardless of the type of pavement mix (Oliver 1989). Normally, the frictional properties of the pavement are highly influenced by the ambient temperature (Khasawneh et al. 2012). Therefore, the lack of proper consideration of the effect of temperature on the skid resistance and hence the braking distance would lead to erroneous maintenance management decisions and pavement performance predictions.
Chassis systems
Published in Tom Denton, Automobile Mechanical and Electrical Systems, 2018
The reason for the development of the anti-lock braking system (ABS) (Fig. 4.115) is simple. Under braking conditions, if one or more of the vehicle’s wheels locks begins to skid, then this has serious consequences: Braking distance increases.Steering control is lost.Tyre wear is abnormal.
Evaluating wet-weather driving safety risks of pavement ruts
Published in Sandra Erkens, Xueyan Liu, Kumar Anupam, Yiqiu Tan, Functional Pavement Design, 2016
Braking distance refers to the locked wheel sliding distance of a vehicle after the driver has applied the brake, until the vehicle has come to a complete stop. Since the tire-pavement friction is the lowest when the wheel is locked, the braking distance so calculated will give a longer distance than the common case of vehicles equipped with anti-lock braking system. It provides a conservative worst case estimate of the braking distance, thus providing some safety margin for safety risk assessment.
Influence of thin water film on asphalt pavement skid resistance: from indoor to in-situ test
Published in International Journal of Pavement Engineering, 2022
Wanli Ye, Shenqing Xiao, Wei Jiang, Jilu Li, Huijie Lv, Yiqiu Tan
Friction, known as the force resisting tires rotating and sliding along the pavement surface, provides the possibility for deceleration and braking of the vehicle and is critical for driving safety and collision avoidance (Ong and Fwa 2007, Mayora and Piña 2009). Insufficient friction prolongs the braking distance of the vehicle under the same conditions, making it mismatch the braking distance estimated by the driver, thereby increasing the possibility of crash accidents (Li et al. 2018). As an essential part of ensuring traffic safety, friction is a critical part that must be considered in pavement maintenance decision-making (Fwa 2017). Under specific operating and environmental conditions, such as the pavement surface being covered by water, the skid resistance of the pavement can drop to deficient levels. Thus, water is of paramount importance regarding pavement skid resistance (Kane et al. 2019). Water on the pavement surface might limit the visibility due to splash and spray and thereby interrupt the traffic (Transportation Officials 2007), which is amplified in areas with high rainfall intensity (Moore 1967, Browne et al. 1972). Further, water accumulated on the pavement surface might reduce the grip and lead to hydroplaning (Bawono et al. 2019). Therefore, considering the skid resistance of water-covered pavement is essential in pavement design. Besides, from the perspective of tribology, there are also many factors affecting the skid resistance of asphalt pavement, such as textures, temperature, and tire-road coupling effect (Kogbara et al. 2016).
Analysis of skid resistance and braking distance of aircraft tire landing on grooved runway pavement
Published in International Journal of Pavement Engineering, 2022
The results indicate that the loss of tire wear significantly decreases friction coefficient and increases braking distance. During the ground rolling process, the reduction of friction coefficient caused by the tire wear effect could be 30% to 50% and the increase of braking distance was around 50%, due to the poor drainage capacity provided by the adverse tread depth. The increase of water film thickness from 1.2 to 3.4 mm reduces friction coefficient by 40% at initial braking speed, but the difference becomes smaller as the speed decreases. The estimated hydroplaning speed for worn tire and 3.4-mm water film thickness is similar to the one based on field measurements, but further increase of water depth would reduce hydroplaning speed. To maintain safe operation during aircraft landing and avoid hydroplaning, the aircraft approach speed should be controlled based on tire wear condition and runway surface water condition.
A risk assessment model for traffic crashes problem using fuzzy logic: a case study of Zonguldak, Turkey
Published in Transportation Letters, 2022
Tires with excessive wear and low tread depth increase the braking distance, which increases the crash risk. It also causes the vehicle to skid on snowy, icy or wet roads. Tire care and tread depth should therefore be taken into consideration. Tires are the only connection between the vehicle and the road, and the tread depth and tire quality are vitally important. Vehicle keeps itself on the track only through the friction force between the tire and the road. Regulations in Turkey require the tires to be replaced when their tread depth falls below 1,6 mm. However, the tire manufacturers recommend replacing summer tires when the tread depth is under 3 mm and winter tires under 4 mm. Retreading is used in Turkey to reduce the cost of tire replacement in heavy machinery. This study focuses on the passenger cars and therefore retreading is not taken into consideration. Tire tread depth measurements were performed with a digital tire tread depth gauge. Three measurements were taken for each tire.”