Mena Mauriello - Academia.edu (original) (raw)

Papers by Mena Mauriello

. However, the scope of this research was not the development of predictive models; instead, the ... more . However, the scope of this research was not the development of predictive models; instead, the goal for the study was the exploratory analysis of pedestrian crashes in Italy to (a) detect interdependence among crash patterns, as well as dissimilarities among patterns; (b) find nontrivial and unsuspected relations in the data; and (c) provide insight for the development of safety improvement strategies focused on pedestrians.

Speeding inconsistently with the road environment is considered to be a major crash contributing ... more Speeding inconsistently with the road environment is considered to be a major crash contributing factor. Estimates are that in about one-third of fatal crashes excessive speeds are involved (1). Most road agencies attempt to achieve the right operating speed among drivers by imposing speed limits. Unfortunately several studies have shown that the speed limit is very much violated and, at best, serves only as a guide to drivers (2-5). The major reason for not obeying speed limits is that the limits are not reflective of roadway conditions and most drivers feel that the limits are lower than what the roadway can accommodate (6).

To improve highway design consistency, several studies developed operating speed prediction model... more To improve highway design consistency, several studies developed operating speed prediction models and investigated drivers' speed behavior. Most existing models are based on spot speed data that assume constant operating speed throughout the horizontal curves and occurrence of acceleration and deceleration only on tangents. To overcome limitations associated with existing models, this study investigated continuous speed profiles with an experiment that used a high-fidelity dynamicdriving simulator on a two-lane highway. A piecewise linear regression model and locally weighted regression scatter-plot smoothing were used to remove noise in the data set while preserving underlying patterns and to identify significant changes in the speed profile. Based on the smoothed speed profiles, models to predict operating speed in curves and in tangents, deceleration and acceleration rates to be used in the operating speed profiles, and starting and ending points of constant operating speed in curve were developed. Radius of the curve notably affected not only the operating speed in the curve but also the operating speed of the tangent following the curve: the smaller the radius, the lower the operating speed of the exit tangent. Both acceleration and deceleration rates increased with curvature. This study found that operating speed was not constant along curves. On small radius curves, deceleration ended close to the center of the curve, and acceleration starts, close to the end of the curve. Increasing the curve radius, the end point of deceleration moves toward the curve's beginning, whereas the start of acceleration moves toward the center of the curve.

This study investigated, by means of a dynamic driving simulator experiment, driver behavior at c... more This study investigated, by means of a dynamic driving simulator experiment, driver behavior at curves on rural two-lane highways in relation to different advance warning signs, perceptual measures, and delineation treatments. The tested treatments were intended to alert drivers to the presence of low-radius curves and to affect their behavior in the approach to the curve as well as along the curve itself. The study results showed that the advance warning signs, perceptual measures, and delineation treatments tested in the driving simulator experiment produced significant effects on driver behavior. The perceptual treatments (i.e., colored transverse strips, dragon teeth markings, colored median island) were the most effective treatments because they produced significant speed reductions in the approach tangent as well as inside the curve. Deceleration behavior in the approach to the curve was affected significantly by the presence of treatments that helped drivers to detect the curve earlier; early detection provided more time to perform deceleration maneuvers at lower rates. The study results strongly supported the real-world implementation of colored transverse strips, dragon teeth markings, and the colored median island. Implementation of the tested measures should be conducted on similar rural highways to validate general application of the results of this study to other regions.

Because the quality of decision making in road safety is dependent on the quality of the data on ... more Because the quality of decision making in road safety is dependent on the quality of the data on which decisions are based, efforts to improve the quality, timeliness, and accuracy of crash databases are crucial. A criticai review of Australasian, European Union, and U.S. crash databases was performed, and future directions were identified. Major issues included procedures for access to crash data, crash report forms, severity of crashes reported in the databases, crash locations, crash classification, and crash severity. Access to crash databases could be provided to approved road safety professionals through a web-based portai, which could also provide detailed police crash reports. The use of electronic crash report forms was strongly recommended because it might solve most ofthe problems associated with paper forms. The severity of crashes reported in the databases varied across countries, and not ali countries reported property-damage-only crashes. However, for both prevention and consistency between countries, collecting property-damage-only crash reports and using them to develop safety strategies is recommended. Combined use of Global Positioning System devices and geographic information systems improves the reporting of crash locations and overcomes traditional problems such as inaccuracies and collection mistakes. To develop effective countermeasures, it is recommended that crashes be classified by the maneuvers and sequence of events for each traffic unit. The adoption of the same system for crash severity classification in different countries would allow comparisons in safety performance between countries and jurisdictions.

Corresponding author: A. Montella, alfonso.montella@unina.it. earlier and naturally to select app... more Corresponding author: A. Montella, alfonso.montella@unina.it. earlier and naturally to select appropriate speeds from their perception of the roadway environment as a whole . Perceptual techniques, albeit not widely used , have low implementation cost and few constraints. In the United States, NCHRP Project 3-74 (10) investigated the effect of vehicle speeds on approaches to intersections and identified several effective perceptual treatments, such as transverse pavement markings, transverse rumble strips, a combination of individual treatments such as lane narrowing and lateral pavement marking, and splitter islands, on each approach. In Australia, Macaulay et al. (11) implemented perceptual peripheral transverse edge lines on the approach to intersections. At the treatment sites, vehicle mean speed decreased on average by 7.7 km/h. In Italy, Montella et al. (7, evaluated seven perpetual treatments on major approaches of rural intersections by means of a driving simulator experiment. The most effective treatments (dragon teeth markings, colored intersection area, and raised median island) produced both a significant speed reduction starting from 250 m before the intersection in the range of 13 to 23 km/h and a significant change in deceleration behavior, with a reduction in the proportion of drivers who did not decelerate.

Several studies have developed operating speed prediction models. Most of the models are based on... more Several studies have developed operating speed prediction models. Most of the models are based on spot speed data, collected by radar guns, pavement sensors, and similar mechanisms. Unfortunately, these data collection methods force the users to assume some invalid assumptions in driver behavior modeling: constant operating speed throughout horizontal curves and occurrence of acceleration and deceleration only on tangents. In this study, an instrumented vehicle with GPS continuous speed tracking was used to analyze driver behavior in terms of speed choice and deceleration or acceleration performance and to develop operating speed prediction models. The data used in the study were from a field experiment conducted in Italy on the rural motorway A16 (Naples–Avellino). Models were developed to predict operating speed in curves and tangents, deceleration and acceleration rates to be used in the operating speed profiles, starting and ending points of constant operating speed in a curve, 85th percentile of the deceleration and acceleration rates of individual drivers, and 85th percentile of the individual drivers' maximum speed reduction in the tangent-to-curve transition. The study results showed that (a) the drivers' speed was not constant along curves, (b) the individual drivers' maximum speed reduction was greater than the operating speed difference in the tangent-to-curve transition, and (c) the deceleration and acceleration rates experienced by individual drivers were greater than the deceleration and acceleration rates used to draw operating speed profiles.

Point-to-point (P2P) speed enforcement is a relatively new approach to traffic law enforcement. I... more Point-to-point (P2P) speed enforcement is a relatively new approach to traffic law enforcement. Its technology allows vehicles whose average speed exceeds the speed limit over the controlled section to be fined. It therefore encourages compliance over distances longer than those where spot enforcement policies have been in place. In this paper, a procedure for consistently setting speed limits with such enforcement systems is proposed. Such a method has been applied to design the speed limits on two motorways in the district of Naples, Italy, where P2P enforcement systems became operational in 2009 and 2010. The speed limits, which were set using the Italian geometric design standard to assess vehicle stability and stopping sight distance, have been compared with those provided by using well-known international standards. The impact of the newly designed speed limits and of the P2P enforcement system on drivers' speeding behaviour has been quantified for each highway section and vehicle type. In fact, accurate measurements of the average travel speeds of each vehicle crossing the enforced sections, before and after the activation of the system, were available. The migration from the old speed limits with spot speed enforcement to the new approach resulted in a notable increase in drivers' compliance to the speed limits with a remarkable decrease in both the average of individual speeds and in their standard deviation. In addition, the analysis of 3 years of data shows that a gradual adaptation of drivers' behaviour to the system took place. In particular, a decreasing compliance to the speed limits points to a non-optimal system management. Finally, the results of a revealed preference survey allowed us to make a behavioural interpretation regarding the significantly different impacts measured on the two motorways.

To improve design consistency of existing and new roads, several studies developed operating spee... more To improve design consistency of existing and new roads, several studies developed operating speed prediction models and investigated drivers' speed behaviour. Most of the existing models are based on spot speed data assuming constant operating speed throughout the horizontal curves and occurrence of acceleration and deceleration only on tangents. To overcome limitations associated with these hypotheses, this study investigated continuous speed profiles of individual drivers by a driving simulator experiment carried out on a two-lane rural highway using the VERA high-fidelity dynamic-driving simulator, operating at the Road Safety Laboratory of University of Naples Federico II (Italy). The experimental route consisted of the succession of 20 tangents with length equal to 1,000 m and curves with radius equal to 400 m. The tangent-to-curve transition was carried out by spiral curves with parameter equal to 150 m and length equal to 55 m. Study results show that speed is not constant along the curve and deceleration rates are considerably higher than acceleration rates. These findings question the traditional hypotheses used to develop operating speed profiles. The analysis of individual drivers' behaviour showed that: (a) 85 th percentile of the speed reduction experienced by individual drivers is more than twice as the operating speed difference in the tangent-to-curve transition, and (b) deceleration and acceleration rates experienced by the individual drivers are approximately double than deceleration and acceleration rates used to draw the operating speed profiles. Study results emphasize that the analysis of the individual speed profiles adds important information to the analysis of the operating speed profile and has the potential to identify supplementary design inconsistencies and safety issues.

Aim of the study was the analysis of powered two-wheeler (PTW) crashes in Italy in order to detec... more Aim of the study was the analysis of powered two-wheeler (PTW) crashes in Italy in order to detect interdependence as well as dissimilarities among crash characteristics and provide insights for the development of safety improvement strategies focused on PTWs. At this aim, data mining techniques were used to analyze the data relative to the 254,575 crashes involving PTWs occurred in Italy in the period 2006–2008. Classification trees analysis and rules discovery were performed. Tree-based methods are non-linear and non-parametric data mining tools for supervised classification and regression problems. They do not require a priori probabilistic knowledge about the phenomena under studying and consider conditional interactions among input data. Rules discovery is the identification of sets of items (i.e., crash patterns) that occur together in a given event (i.e., a crash in our study) more often than they would if they were independent of each other. Thus, the method can detect interdependence among crash characteristics. Due to the large number of patterns considered, both methods suffer from an extreme risk of finding patterns that appear due to chance alone. To overcome this problem, in our study we randomly split the sample data in two data sets and used well-established statistical practices to evaluate the statistical significance of the results. Both the classification trees and the rules discovery were effective in providing meaningful insights about PTW crash characteristics and their interdependencies. Even though in several cases different crash characteristics were highlighted, the results of the two the analysis methods were never contradictory. Furthermore, most of the findings of this study were consistent with the results of previous studies which used different analytical techniques, such as probabilistic models of crash injury severity. Basing on the analysis results, engineering countermeasures and policy initiatives to reduce PTW injuries and fatalities were singled out. The simultaneous use of classification trees and association discovery must not, however, be seen as an attempt to supplant other techniques, but as a complementary method which can be integrated into other safety analyses.

The paper investigated drivers' speed behaviour in a section of a rural highway crossing a small ... more The paper investigated drivers' speed behaviour in a section of a rural highway crossing a small urban community in the existing scenario without any traffic calming device and in two different design scenarios with traffic calming in the urban community. Two gateways and four integrative traffic calming devices along the route within the urban area were tested. The gateways were aimed at slowing down the vehicles entering in the built-up area, while the traffic calming devices were aimed at complementing the gateway effect inside the built-up area. Two design options were tested: first option (alt1) is a combination of low cost measures, whereas the second option (alt2) is more expensive as includes a chicane and requires land acquisition. Drivers' behaviour was investigated by means of a driving simulator experiment. The VERA dynamic-driving simulator operating at the TEST Road Safety Laboratory located in Naples (Italy) was used. Simulation results were validated by the comparison of speed behaviour in the real world and in the driving simulator, in the scenario without traffic calming. Analysis of the driving simulator experiment results was performed using two different approaches: (a) explorative description of data by cluster analysis; (b) inferential procedures about population using statistical tests. Cluster analysis was carried out in order to test if the drivers' speed behaviour in the different design alternatives was substantially different. Statistical tests were performed in order to verify if speeds in specific sections were significantly different. Cluster analysis looked at speed profiles, whereas statistical tests looked at speed data in specific points. The obtained results showed a different behaviour of drivers approaching the urban community in the existing scenario and in the design scenarios. In the south direction, mean speed reduction ranging between 16 and 17 km/h, with 5% level of significance, was observed. In the north direction, mean speed reduction equal to 11 km/h, with 10% level of significance, was observed. Differences between the two design alternatives were not statistically significant. Along the urban community, a statistically significant mean speed reduction ranging between 9 and 15 km/h was observed in the south direction. In the north direction, speed reduction was not statistically significant. Overall, combined results of cluster analysis and statistical tests showed that the treatments were more effective in the direction with higher speeds in the base scenario.

In this paper, we evaluated the effects on speed and safety of the point-to-point (P2P) speed enf... more 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. The P2P system led to very positive effects on both speed and safety. As far as the effects on the section average travel speeds, the system yielded to a reduction in the mean speed, the 85th percentile speed, the standard deviation of speed, and the proportion of drivers exceeding the speed limits, exceeding the speed limits more than 10 km/h, and exceeding the speed limits more than 20 km/h. The best results were the decrease of the speed variability and the reduction of the excessive speeding behaviour. The decrease in the standard deviation of speed was 26% while the proportion of light and heavy vehicles exceeding the speed limits more than 20 km/h was reduced respectively by 84 and 77%. As far as the safety effects, the P2P system yielded to a 32% reduction in the total crashes, with a lower 95% confidence limit of the estimate equal to 22%. The greatest crash reductions were in rainy weather (57%), on wet pavement (51%), on curves (49%), for single vehicle crashes (44%), and for injury crashes (37%). It is noteworthy that the system produced a statistically significant reduction of 21% in total crashes also in the part of the motorway where it was not activated, thus generating a significant spillover effect. The investigation of the effects of the P2P system on speed and safety over time allowed to develop crash modification functions where the relationship between crash modification factors and speed parameters (mean speed, 85th percentile speed, and standard deviation of speed) was expressed by a power function. Crash modification functions show that the effect of speed on safety is greater on curves and for injury crashes. Even though the study results show excellent outcomes, we must point out that the crash reduction effects decreased over time and speed, speed variability, and non-compliance to speed limits significantly increased over time. To maintain its effectiveness over time, P2P speed enforcement must be actively managed, i.e. constantly monitored and supported by appropriate sanctions.