Papers by Alfonso Montela
Transportation Research Record: Journal of the Transportation Research Board, 2015
This paper investigated, by means of a dynamic driving-simulator experiment, drivers' behavio... more This paper investigated, by means of a dynamic driving-simulator experiment, drivers' 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 curves, prompting a reduction in curve approach speeds, and to affect drivers' speed as they drove through curves. A benefit–cost analysis was performed to determine the economic feasibility of applying the countermeasures to speeding tested in the driving simulator. Study results showed that all the treatments produced significant effects on drivers' speed behavior at curves on rural two-lane highways. The perceptual treatments (i.e., colored transverse strips, dragon-teeth markings, and colored median island) were the most effective. The safety benefits measured in lower crash costs arising from speed reductions were much greater than the costs of the alternatives. The most...
Transportation Research Part C: Emerging Technologies, 2015
Accident Analysis & Prevention, 2015
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.
Transportation Research Record: Journal of the Transportation Research Board, 2007
The methodological approach to safety evaluation of two-lane rural highway segments that is prese... more The methodological approach to safety evaluation of two-lane rural highway segments that is presented uses both analytical procedures referring to alignment design consistency models and safety inspection processes. A safety index (SI) that quantitatively measures the relative safety performance of a road segment is calculated from the procedure. The SI is formulated by combining three components of risk: the exposure of road users to road hazards, the probability of a vehicle's being involved in an accident, and the resulting consequences should an accident occur. This systematic and replicable procedure integrates two different, complementary approaches–one based on design consistency evaluations and the other on safety inspections–and makes it possible to address a wide variety of safety issues effectively. A further advantage of the procedure is its applicability on highways where crash data are either not available or unreliable. Validation of the procedure was carried out ...
Transportation Research Record: Journal of the Transportation Research Board, 2010
The aim of this paper is to investigate, by means of a dynamic driving simulator experiment, the ... more The aim of this paper is to investigate, by means of a dynamic driving simulator experiment, the behavior of road users at rural intersections in relation to perceptual measures designed for increasing hazard detection. In the experiment 10 configurations of tangents were tested: Alt1, base tangent; Alt2, four-leg base intersection; Alt3, intersection with reduced sight distance; and Alt4 through Alt10, intersections with perceptual treatments. The Virtual Environment for Road Safety high-fidelity dynamic-driving simulator, operating at the Technology Environment Safety Transport Road Safety Laboratory located in Naples, Italy, was used. Analysis of the results used two approaches: (a) explorative description of data by cluster analysis and (b) inferential procedures about population using statistical tests. Results showed that the speed behavior in the tangents was significantly affected by the presence of the intersections and by the perceptual treatments. Intersections without pe...
Transportation Research Record: Journal of the Transportation Research Board, 2011
Road safety inspections (RSIs) are becoming an accepted practice in many agencies around the worl... more Road safety inspections (RSIs) are becoming an accepted practice in many agencies around the world. A safety assessment procedure based on safety inspections that can be used as a supporting tool in the safety management of low-volume rural roads is presented. From the procedure, a safety index (SI) that quantitatively measures the relative safety performance of a road segment is calculated. The RSIs carried out according to the defined procedures showed that, for the majority of the safety issues, there was a statistically significant level of agreement on the ranking of the issues produced by different inspectors. Further, the SI was assessed in 30 segments of two-lane rural roads, and rankings performed according to the SI scores and according to the empirical Bayes (EB) safety estimates were compared. This comparison showed a good correlation between SI and EB estimates. The results from the Spearman's rank correlation analysis provide additional validation of the procedure,...
Transportation Research Record: Journal of the Transportation Research Board, 1999
Vehicles that collide with highway safety features do not always produce the same effects. The ou... more Vehicles that collide with highway safety features do not always produce the same effects. The outcome for each vehicle that collides with a feature will be different, depending greatly not only on its mass, velocity, and impact angle but also on the position of its center of mass and ...
Transportation Research Record: Journal of the Transportation Research Board, 2013
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 critical 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 portal, which could also provide detailed police crash reports. The use of electronic crash report forms was strongly recommended because it might solve most of the problems associated with paper forms. The severity of crashes reported in the databases varied across countries, and not all countries reported property-damage-only crashes. However, for both prevention...
Le intersezioni costituiscono solo una piccola parte dell'intero sistema stradale, ma è nell... more Le intersezioni costituiscono solo una piccola parte dell'intero sistema stradale, ma è nelle intersezioni che si verificano la maggior parte degli incidenti: oltre il 50% del totale nelle aree urbane e oltre il 30% nelle aree extraurbane. La maggior parte degli incidenti è causata da errori umani che i guidatori compiono a causa delle limitazioni fisiche, percettive e cognitive proprie degli esseri umani. Spesso i guidatori non percepiscono in tempo l'intersezione approcciando ad essa con velocità elevata e, come ben noto, con l' ...
4th International SIIV Congress, 2007
In the contest of the EU program “Road Safety in EU: the 1997-2001 program”, the “IASP” project, ... more In the contest of the EU program “Road Safety in EU: the 1997-2001 program”, the “IASP” project, proposed by the Province of Catania with the scientific support of the Department of Civil and Environmental Engineering of University of Catania, was approved and co-funded by European Commission (DG TREN). A methodological approach for the safety evaluation of two-lane rural highway segments that uses both analytical procedures referring to road safety inspection processes and alignment design consistency models is ...
International Conference Road Safety on Four Continents, Varsavia (PL), Oct 1, 2005
Nowadays, Road Safety Inspections (RSI) are recognized as an effective tool for identifying safet... more Nowadays, Road Safety Inspections (RSI) are recognized as an effective tool for identifying safety deficiencies of road infrastructures. They represent a low cost process for the evaluation of the network safety performance. Its applicability in rural local roads, where accident data generally do not give enough information for the safety analysis, make the procedure very attractive. However, due to the subjective nature of the process RSI may give rise to disagreements which limit their effectiveness. The paper describes the RSI ...
ARACNE, Rome, Italy, 2008
Just reproduction or copying of single parts of this volume is permitted for study, discussion, d... more Just reproduction or copying of single parts of this volume is permitted for study, discussion, documentation or teaching purposes on the condition that authors and sources are cited.
The Baltic Journal of …, 2006
Road Safety Inspections (RSI) are recognized as an effective tool for identifying safety issues. ... more Road Safety Inspections (RSI) are recognized as an effective tool for identifying safety issues. However, due to the subjective nature of the process, they may give rise to disagreements which limit their effectiveness. In the framework of the IASP research program sponsored ...
… Board 88th Annual …, 2009
The paper investigated drivers' speed behavior in rural highways crossing small urban commun... more The paper investigated drivers' speed behavior in rural highways crossing small urban communities both without any gateway and traffic calming device and with different configurations of gateway and traffic calming along the urban environment. Speeds in entrance to small urban areas ...
Accident Analysis & Prevention, 2011
Accident Analysis & Prevention, 2012
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.
Le Strade, Special Issue 23rd PIARC …, 2007
1 INTRODUCTION Road safety evaluations on two-lane rural roads with low/medium traffic flows can ... more 1 INTRODUCTION Road safety evaluations on two-lane rural roads with low/medium traffic flows can raise concerns both due to the general deficiency of reliable data on road accidents and to the circumstance that few crash data due to low traffic, not always can give enough ...
ABSTRACT To improve design consistency of existing and new roads, several studies developed opera... more ABSTRACT 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.
Procedia - Social and Behavioral Sciences, 2012
Crash data collection is crucial for road safety improvement, but Italy is considerably behind th... more Crash data collection is crucial for road safety improvement, but Italy is considerably behind the best international practices. To help to bridge this gap, a critical review of international crash databases was carried out and recommendations for improvement of the Italian police crash data collection and the national crash database were formulated. Main issues identified in the research are related to the database access procedures, the crash report, the crash location, the crash classification, and the severity classification.
Procedia - Social and Behavioral Sciences, 2012
The paper presents a critical review of the Australasian, EU and US roundabout geometric design s... more The paper presents a critical review of the Australasian, EU and US roundabout geometric design standards and guidelines and identifies inconsistencies of the Italian roundabout standard which deserve improvement. As a result, recommendations for improvement of the Italian standard are proposed. These recommendations are mainly based on the concepts of design flexibility and performance based design. Indeed, rigid standards which do not really take into account safety and operational consequences of the design decisions and the need to balance opposite demands might produce undesirable outcomes.
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Papers by Alfonso Montela