Effects on speed and safety of point-to-point speed enforcement systems: Evaluation on the urban motorway A56 Tangenziale di Napoli

In this paper, we evaluated the effects on speed and safety of the point-to-point (P2P) speed enforcement system activated on the urban motorway A56 in Italy. The P2P speed enforcement is a relatively new approach to traffic law enforcement that involves the calculation of the average speed over a section. To evaluate the speed effects, we performed a before–after analysis of speed data investigating also effects on non-compliance to speed limits. To evaluate the safety effects, we carried out an empirical Bayes observational before-and-after study.     

Evidence that attitude accessibility augments the relationship between speeding attitudes and speeding behavior: A test of the MODE model in the context of driving

According to the MODE model of attitude-to-behavior processes, attitude accessibility augments attitude–behavior correspondence, reflecting an automatic influence of attitudes on behavior. We therefore tested whether attitude accessibility moderates the attitude–behavior relationship in a context that is governed by characteristically automatic behavior, namely driving. In study 1 (correlational design), participants (N = 130) completed online questionnaire measures of the valences and accessibilities of their attitudes towards speeding. Two weeks later, online questionnaire measures of subsequent speeding behavior were obtained. Attitude valence was a significantly better predictor of behavior at high (mean + 1SD) versus low (mean – 1SD) levels of attitude accessibility. In study 2 (experimental design), attitude accessibility was manipulated with a repeated attitude expression task. Immediately after the manipulation, participants (N = 122) completed online questionnaire measures of attitude valence and accessibility, and two weeks later, subsequent speeding behavior. Increased attitude accessibility in the experimental (versus control) condition generated an increase in attitude–behavior correspondence. The findings are consistent with the MODE model’s proposition that attitudes can exert an automatic influence on behavior. Interventions to reduce speeding could usefully increase the accessibility of anti-speeding attitudes and reduce the accessibility of pro-speeding attitudes.     

Fractions of fatal crashes attributable to speeding: Evolution for the period 2001–2010 in France

Road safety is a major concern in the West, especially in France. Among all the established risk factors for fatal crashes, speed is specific in two ways: every road-user is exposed to it, and it increases not only crash rates but also the severity of crashes. Thus, speed regulation is of primary importance in road-safety policy and has also generated much public debate. To contribute to this debate, we constructed a power-model which relates the number of fatal crashes to speed raised to the power four. Despite its simplicity, this model fitted the data well. Notably, it enabled the fractions of fatal crashes attributable to various levels of speeding to be estimated. Data for secondary roads over the period 2001–2010 showed that the fraction of fatal crashes attributable to high-level speeding (>20 kph over the speed limit) decreased from 25% to 6% and that attributable to medium-level speeding (10–20 kph over the speed limit) decreased from 13% to 9%, whereas that attributable to low-level speeding progressively increased from 7% to 13%. Similar trends were observed on main roads. These results highlight the effectiveness of the speed regulation policies introduced during the study period with respect to high-level speeding. They also suggest that future policy should focus on low and medium-level speeding in order further to reduce road deaths significantly, since these levels now correspond to the major fraction of fatal crashes.     

The observed effects of teenage passengers on the risky driving behavior of teenage drivers

The association between teenage passengers and crash risks among young drivers may be due to risky driving behavior. We investigated the effect on two measures of risky driving in the presence of young male and female passengers. Vehicles exiting from parking lots at 10 high schools were observed and the occupants were identified by gender and age (teen or adult). At a nearby site, the speed and headway of passing traffic were recorded using video and LIDAR technology. Teenage drivers drove faster than the general traffic and allowed shorter headways, particularly in the presence of a male teenage passenger. Both male and female teenage drivers allowed shorter headways (relative to no passenger or a female passenger) in the presence of a male teenage passenger, while the presence of a female teenage passenger resulted in longer headways for male teenage drivers. Overall, the observed rate of high risk driving (defined as speed > or =15 mph or more above the posted speed limit and/or headway of < or =1.0 s) for the teen male driver/male passenger condition was about double that of general traffic. In conclusion, the presence of male teenage passengers was associated with risky driving behavior among teenage drivers.     

Speeding by young novice drivers: What can personal characteristics and psychosocial theory add to our understanding?

Purpose

Young novice drivers continue to be overrepresented in fatalities and injuries arising from crashes even with the introduction of countermeasures such as graduated driver licensing (GDL). Enhancing countermeasures requires a better understanding of the variables influencing risky driving. One of the most common risky behaviours performed by drivers of all ages is speeding, which is particularly risky for young novice drivers who, due to their driving inexperience, have difficulty in identifying and responding appropriately to road hazards. Psychosocial theory can improve our understanding of contributors to speeding, thereby informing countermeasure development and evaluation. This paper reports an application of Akers’ social learning theory (SLT), augmented by Gerrard and Gibbons’ prototype/willingness model (PWM), in addition to personal characteristics of age, gender, car ownership, and psychological traits/states of anxiety, depression, sensation seeking propensity and reward sensitivity, to examine the influences on self-reported speeding of young novice drivers with a Provisional (intermediate) licence in Queensland, Australia.

Method

Young drivers (n = 378) recruited in 2010 for longitudinal research completed two surveys containing the Behaviour of Young Novice Drivers Scale, and reported their attitudes and behaviours as pre-Licence/Learner (Survey 1) and Provisional (Survey 2) drivers and their sociodemographic characteristics.

Results

An Akers’ measurement model was created. Hierarchical multiple regressions revealed that (1) personal characteristics (PC) explained 20.3%; (2) the combination of PC and SLT explained 41.1%; (3) the combination of PC, SLT and PWM explained 53.7% of variance in self-reported speeding. Whilst there appeared to be considerable shared variance, the significant predictors in the final model included gender, car ownership, reward sensitivity, depression, personal attitudes, and Learner speeding.

Conclusions

These results highlight the capacity for psychosocial theory to improve our understanding of speeding by young novice drivers, revealing relationships between previous behaviour, attitudes, psychosocial characteristics and speeding. The findings suggest multi-faceted countermeasures should target the risky behaviour of Learners, and Learner supervisors should be encouraged to monitor their Learners’ driving speed. Novice drivers should be discouraged from developing risky attitudes towards speeding.     

Effectiveness and acceptance of the intelligent speeding prediction system (ISPS)

Background

The intelligent speeding prediction system (ISPS) is an in-vehicle speed assistance system developed to provide quantitative predictions of speeding. Although the ISPS's prediction of speeding has been validated, whether the ISPS can regulate a driver's speed behavior or whether a driver accepts the ISPS needs further investigation. Additionally, compared to the existing intelligent speed adaptation (ISA) system, whether the ISPS performs better in terms of reducing excessive speeds and improving driving safety needs more direct evidence.

Objectives

An experiment was conducted to assess and compare the effectiveness and acceptance of the ISPS and the ISA.

Method

We conducted a driving simulator study with 40 participants. System type served as a between-subjects variable with four levels: no speed assistance system, pre-warning system developed based on the ISPS, post-warning system ISA, and combined pre-warning and ISA system. Speeding criterion served as a within-subjects variable with two levels: lower (posted speed limit plus 1 mph) and higher (posted speed limit plus 5 mph) speed threshold. Several aspects of the participants’ driving speed, speeding measures, lead vehicle response, and subjective measures were collected.

Results

Both pre-warning and combined systems led to greater minimum time-to-collision. The combined system resulted in slower driving speed, fewer speeding exceedances, shorter speeding duration, and smaller speeding magnitude.

Conclusions

The results indicate that both pre-warning and combined systems have the potential to improve driving safety and performance.     

煤炭表面改质技术及设备在东曲矿选煤厂的应用

阐述了一种新型的采用高剪切力的煤炭表面改质技术及设备在东曲矿选煤厂的应用,该厂通过对表面改质机内部结构与工作过程的分析研究,以及单机试验和工业运行试验,初步探讨了表面改质机的作用机理,经现场连续带负荷生产后,能显著提高浮选速度和精煤回收率.     

硬质合金YG8高速磨削工艺试验研究

采用树脂结合剂金刚石砂轮,对硬质合金YG8进行了高速磨削工艺试验研究,测得了不同砂轮线速度、磨削深度和工作台速度条件下的磨削力和表面粗糙度,并对磨削的表面形貌进行了观测,揭示了硬质合金YG8高速磨削的材料去除机理。试验结果表明:将高速磨削技术应用于硬质合金材料的加工是一种切实可行的加工方法,能得到较好的表面质量并提高加工效率。随着砂轮线速度的增加,或者工作台速度和磨削深度的减小,磨削的最大未变形切屑厚度减小,磨削力减小,材料的比磨削能增加,使得工件的加工表面质量得到改善。     

OBB层次结构及其应用加速算法的研究

层次包围盒在碰撞检测中的应用对于提高碰撞检测精确度以及减少碰撞检测复杂度起着十分重要的作用。该文介绍了OBB包围盒的计算、相交测试以及构造方法,将一种加速碰撞检测搜索算法与其结合,并且讨论了时间复杂度。