Currently, the speed limit for tractor-trailers (TTs) on Egyptian highways is 30 km/h lower than ... more Currently, the speed limit for tractor-trailers (TTs) on Egyptian highways is 30 km/h lower than the speed limit for passenger cars (PCs). The main purpose of this article is therefore to evaluate the effects of an increase in TT speed limit on both the traffic safety and mobility of Egyptian three-lane highways, with speed limits of 90 and 100 km/h for PCs. A SUMO simulation model was used in this analysis. Average vehicle delay was used as a measure of mobility, while the simulated conflict ratio based on time to collision (TTC) and deceleration rate required to avoid crash (DRAC) surrogate safety measures were used as performance indicators of safety. All simulated vehicles were equipped with surrogate safety measurement (SSM) devices to extract traffic conflicts, with TTC ≤ 2.50 representing less sever conflicts; TTC ≤ 1.50 s and DRAC ≥ 3.35 m/s2 representing potential conflicts; and TTC ≤ 0.50 s and DRAC ≥ 6.0 m/s2 representing severe conflicts. The results show that increasing...
Due to recent advances in the Vehicular Internet of Things (VIoT), a large volume of traffic traj... more Due to recent advances in the Vehicular Internet of Things (VIoT), a large volume of traffic trajectory data has been generated. The trajectory data is highly unstructured and pre-processing it is a very cumbersome task, due to the complexity of the traffic data. However, the accuracy of traffic flow learning models depends on the quantity and quality of preprocessed data. Hence, there is a significant gap between the size and quality of benchmarked traffic datasets and the respective learning models. Additionally, generating a custom traffic dataset with required feature points in a constrained environment is very difficult. This research aims to harness the power of the deep learning hybrid model with datasets that have fewer feature points. Therefore, a hybrid deep learning model that extracts the optimal feature points from the existing dataset using a stacked autoencoder is presented. Handcrafted feature points are fed into the hybrid deep neural network to predict the travel p...
This study presents a mode choice (MC) behavioural model for individuals’ trips in Mansoura City ... more This study presents a mode choice (MC) behavioural model for individuals’ trips in Mansoura City in Egypt. Mansoura city lies in the delta region and considered as one of the most crowded cities in Egypt. The absence of effective application of urban transportation planning process in the city results in deficiencies in choosing the suitable transport policies to reduce the transportation related problems resulting from urban development and fast population increase. Mansoura does not have a transportation model; hence, developing a mode choice model for the city is considered very crucial for predicting the use of each mode, and the factors that affect selecting a specific mode. Around 10,000 online questionnaires were collected in 2015 using Google Forms. These questionnaires represent around 30,000 individual trips. In this study, only persons older than 13-years old were considered (i.e., 15,265 records). Two-thirds of the data were randomly selected and used in developing the M...
A good understanding of the relationship between highway performance, such as crash rates and tra... more A good understanding of the relationship between highway performance, such as crash rates and travel delays, and winter road maintenance activities under different winter weather and traffic conditions is essential to the development of cost-effective winter road maintenance policies and standards, operation strategies and technologies. This research is specifically concerned about the mobility benefit of winter road maintenance. A microscopic traffic simulation model is used to investigate the traffic patterns under adverse weather and road surface conditions. A segment of the Queen Elizabeth Way (QEW) located in the Great Toronto Area, Ontario is used in the simulation study. Observed field traffic data from the study segment was used in the calibration of the simulation model. Different scenarios of traffic characteristics and road surface conditions as a result of weather events and maintenance operations are simulated and travel time is used as a performance measure for the eff...
In safety analysis, two questions typically need to be addressed: 1) how to identify unsafe sites... more In safety analysis, two questions typically need to be addressed: 1) how to identify unsafe sites for priority intervention? and 2) how to determine the effectiveness of treatments introduced at these and other sites? Two types of approaches have been considered in the literature to provide answers for these questions: (1) observational models based on historical crash data and (2) observed or simulated higher risk vehicle interactions or traffic conflicts. Observational crash-based models are good at predicting higher severity crashes, but they tend to ignore higher risk vehicle interactions that compromise safety, that have not resulted in crashes (e.g. near misses). Proponents of microscopic simulation argue that ignoring these higher risk interactions can severely understate the safety problem at a given site and lead to a misallocation of scarce treatment funds. Another problem with observational crash prediction models is the need for sufficient crash data reported over an ext...
The time headway distribution of vehicles plays a significant role in different traffic engineeri... more The time headway distribution of vehicles plays a significant role in different traffic engineering applications. This paper investigated seven probability distributions that would mimic the distribution of the time headways on the Egyptian two-lane, two-way (TLTW) roads, namely (1) exponential, (2) lognormal, (3) gamma, (4) inverse Gaussian, (5) Pearson type III, (6) shifted exponential, and (7) Schuhl distributions. Two sites from two rural TLTW roads that connect Mansoura city to Damietta and Dikirnis cities are studied. One-hour videotaped data from each site were collected, for both directions. Besides, the Chi-square and the K–S goodness-of-fit (GOF) measures were used to assess which distribution fits the observed headway data better. Based on the observed data, about 75% of travel speed measurements are relatively closer in values (between 60 and 70 km/h) for both directions. Different bin widths (0.50, 1.0, and 2.0 s) along with the recommended bin size (3.0 s) by the Rice ...
This paper presents the development of safety performance functions (SPFs) for major rural arteri... more This paper presents the development of safety performance functions (SPFs) for major rural arterial roads in Egypt. Four segmentation methods were used for the SPFs development: (1) constant section length of one kilometer (S1), because crash data are reported for every kilometer; (2) homogenous sections (S2), following the highway safety manual (HSM) recommendation; (3) variable sections with respect to the presence of curvatures (S3); and (4) variable sections with respect to the presence of both curvatures and U-turns (S4). The generalized linear modeling technique was used for SPFs development using the stepwise procedure, with/without considering time effect (i.e. year-to-year variation). The Akaike information criterion, Pearson product-moment correlation coefficient, and mean prediction bias along with the cumulative residual (CURE) plots are used to evaluate the prediction accuracy of the proposed models. The segmentation method was found to affect the prediction accuracy of...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given location for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, i.e., to actual safety performance, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting and evaluating cost-effective treatments. This paper presents a statistical relationship between observed crashes and simulated traffic conflicts for a range of conflict thresholds and simulation runs. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulation platform. The...
This paper examines the transferability of the Safety Performance Function (SPF) of the Highway S... more This paper examines the transferability of the Safety Performance Function (SPF) of the Highway Safety Manual (HSM) and other 10 international SPFs for total crashes on rural multi-lane divided roads in Egypt. Four segmentation approaches are assessed in the transferability of the international SPFs, namely: (1) one-kilometer segments (S1); (2) homogenous sections (S2); (3) variable segments with respect to the presence of curvatures (S3); and (4) variable segments with respect to the presence of both curvatures and U-turns (S4). The Mean Absolute Deviation (MAD), Mean Prediction Bias (MPB), Mean Absolute Percentage Error (MAPE), Pearson χ2 statistic, and Z-score parameters are used to evaluate the performance of the transferred models. The overdispersion parameter (k) for each transferred model and each segmentation approach is recalibrated using the local data by the maximum likelihood method. Before estimating the transferability calibration factor (Cr), three methods were used t...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given location for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, i.e., to actual safety performance, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting and evaluating cost-effective treatments. This paper presents a statistical relationship between observed crashes and simulated traffic conflicts for a range of conflict thresholds and simulation runs. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulation platform. The...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given site for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting cost-effective treatments. This paper presents different statistical relationships between observed crashes and simulated traffic conflicts for a range of conflict thresholds. These models are then compared with conventional crash-volume prediction models. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulatio...
One of the main inputs for flexible pavement design is the strength of the Unbound Granular Mater... more One of the main inputs for flexible pavement design is the strength of the Unbound Granular Materials (UGMs) and subgrade soils. In Egypt, California Bearing Ratio (CBR) is used to characterize the strength of UGMs and subgrade soils for pavement structural design. The CBR can be measured either in the laboratory or in the field. The CBR test is tedious, laborious and time consuming. This paper presents the applications of Multiple Linear Regression Analysis (MLR) and Artificial Neural Networks (ANNs) to develop CBR models through soil index properties. Database containing 120 measured CBR values along with the index properties was gathered from the quality control reports prepared at the Highway and Airport Engineering Laboratory, Mansoura University. The index properties were gradation, Atterberg limits, American Association of State Highways and Transportation Officials (AASHTO) soil classification and compaction parameters according to the modified Proctor test. CBR values ranged between 12% and 95% for unbound granular materials and subgrade soils. A CBR model was proposed as a function of Maximum Dry Density (MDD), grading modulus (GM) and percentage of retained on sieve No.10 (R#10). The GM is the summation of the passing percentage of the sieves, No. 40, No. 10 and No. 200 divided by 100. The coefficient of determination (R 2) was found to be 0.92 for MLR and 0.88 for the ANNs.
Currently, the speed limit for tractor-trailers (TTs) on Egyptian highways is 30 km/h lower than ... more Currently, the speed limit for tractor-trailers (TTs) on Egyptian highways is 30 km/h lower than the speed limit for passenger cars (PCs). The main purpose of this article is therefore to evaluate the effects of an increase in TT speed limit on both the traffic safety and mobility of Egyptian three-lane highways, with speed limits of 90 and 100 km/h for PCs. A SUMO simulation model was used in this analysis. Average vehicle delay was used as a measure of mobility, while the simulated conflict ratio based on time to collision (TTC) and deceleration rate required to avoid crash (DRAC) surrogate safety measures were used as performance indicators of safety. All simulated vehicles were equipped with surrogate safety measurement (SSM) devices to extract traffic conflicts, with TTC ≤ 2.50 representing less sever conflicts; TTC ≤ 1.50 s and DRAC ≥ 3.35 m/s2 representing potential conflicts; and TTC ≤ 0.50 s and DRAC ≥ 6.0 m/s2 representing severe conflicts. The results show that increasing...
Due to recent advances in the Vehicular Internet of Things (VIoT), a large volume of traffic traj... more Due to recent advances in the Vehicular Internet of Things (VIoT), a large volume of traffic trajectory data has been generated. The trajectory data is highly unstructured and pre-processing it is a very cumbersome task, due to the complexity of the traffic data. However, the accuracy of traffic flow learning models depends on the quantity and quality of preprocessed data. Hence, there is a significant gap between the size and quality of benchmarked traffic datasets and the respective learning models. Additionally, generating a custom traffic dataset with required feature points in a constrained environment is very difficult. This research aims to harness the power of the deep learning hybrid model with datasets that have fewer feature points. Therefore, a hybrid deep learning model that extracts the optimal feature points from the existing dataset using a stacked autoencoder is presented. Handcrafted feature points are fed into the hybrid deep neural network to predict the travel p...
This study presents a mode choice (MC) behavioural model for individuals’ trips in Mansoura City ... more This study presents a mode choice (MC) behavioural model for individuals’ trips in Mansoura City in Egypt. Mansoura city lies in the delta region and considered as one of the most crowded cities in Egypt. The absence of effective application of urban transportation planning process in the city results in deficiencies in choosing the suitable transport policies to reduce the transportation related problems resulting from urban development and fast population increase. Mansoura does not have a transportation model; hence, developing a mode choice model for the city is considered very crucial for predicting the use of each mode, and the factors that affect selecting a specific mode. Around 10,000 online questionnaires were collected in 2015 using Google Forms. These questionnaires represent around 30,000 individual trips. In this study, only persons older than 13-years old were considered (i.e., 15,265 records). Two-thirds of the data were randomly selected and used in developing the M...
A good understanding of the relationship between highway performance, such as crash rates and tra... more A good understanding of the relationship between highway performance, such as crash rates and travel delays, and winter road maintenance activities under different winter weather and traffic conditions is essential to the development of cost-effective winter road maintenance policies and standards, operation strategies and technologies. This research is specifically concerned about the mobility benefit of winter road maintenance. A microscopic traffic simulation model is used to investigate the traffic patterns under adverse weather and road surface conditions. A segment of the Queen Elizabeth Way (QEW) located in the Great Toronto Area, Ontario is used in the simulation study. Observed field traffic data from the study segment was used in the calibration of the simulation model. Different scenarios of traffic characteristics and road surface conditions as a result of weather events and maintenance operations are simulated and travel time is used as a performance measure for the eff...
In safety analysis, two questions typically need to be addressed: 1) how to identify unsafe sites... more In safety analysis, two questions typically need to be addressed: 1) how to identify unsafe sites for priority intervention? and 2) how to determine the effectiveness of treatments introduced at these and other sites? Two types of approaches have been considered in the literature to provide answers for these questions: (1) observational models based on historical crash data and (2) observed or simulated higher risk vehicle interactions or traffic conflicts. Observational crash-based models are good at predicting higher severity crashes, but they tend to ignore higher risk vehicle interactions that compromise safety, that have not resulted in crashes (e.g. near misses). Proponents of microscopic simulation argue that ignoring these higher risk interactions can severely understate the safety problem at a given site and lead to a misallocation of scarce treatment funds. Another problem with observational crash prediction models is the need for sufficient crash data reported over an ext...
The time headway distribution of vehicles plays a significant role in different traffic engineeri... more The time headway distribution of vehicles plays a significant role in different traffic engineering applications. This paper investigated seven probability distributions that would mimic the distribution of the time headways on the Egyptian two-lane, two-way (TLTW) roads, namely (1) exponential, (2) lognormal, (3) gamma, (4) inverse Gaussian, (5) Pearson type III, (6) shifted exponential, and (7) Schuhl distributions. Two sites from two rural TLTW roads that connect Mansoura city to Damietta and Dikirnis cities are studied. One-hour videotaped data from each site were collected, for both directions. Besides, the Chi-square and the K–S goodness-of-fit (GOF) measures were used to assess which distribution fits the observed headway data better. Based on the observed data, about 75% of travel speed measurements are relatively closer in values (between 60 and 70 km/h) for both directions. Different bin widths (0.50, 1.0, and 2.0 s) along with the recommended bin size (3.0 s) by the Rice ...
This paper presents the development of safety performance functions (SPFs) for major rural arteri... more This paper presents the development of safety performance functions (SPFs) for major rural arterial roads in Egypt. Four segmentation methods were used for the SPFs development: (1) constant section length of one kilometer (S1), because crash data are reported for every kilometer; (2) homogenous sections (S2), following the highway safety manual (HSM) recommendation; (3) variable sections with respect to the presence of curvatures (S3); and (4) variable sections with respect to the presence of both curvatures and U-turns (S4). The generalized linear modeling technique was used for SPFs development using the stepwise procedure, with/without considering time effect (i.e. year-to-year variation). The Akaike information criterion, Pearson product-moment correlation coefficient, and mean prediction bias along with the cumulative residual (CURE) plots are used to evaluate the prediction accuracy of the proposed models. The segmentation method was found to affect the prediction accuracy of...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given location for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, i.e., to actual safety performance, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting and evaluating cost-effective treatments. This paper presents a statistical relationship between observed crashes and simulated traffic conflicts for a range of conflict thresholds and simulation runs. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulation platform. The...
This paper examines the transferability of the Safety Performance Function (SPF) of the Highway S... more This paper examines the transferability of the Safety Performance Function (SPF) of the Highway Safety Manual (HSM) and other 10 international SPFs for total crashes on rural multi-lane divided roads in Egypt. Four segmentation approaches are assessed in the transferability of the international SPFs, namely: (1) one-kilometer segments (S1); (2) homogenous sections (S2); (3) variable segments with respect to the presence of curvatures (S3); and (4) variable segments with respect to the presence of both curvatures and U-turns (S4). The Mean Absolute Deviation (MAD), Mean Prediction Bias (MPB), Mean Absolute Percentage Error (MAPE), Pearson χ2 statistic, and Z-score parameters are used to evaluate the performance of the transferred models. The overdispersion parameter (k) for each transferred model and each segmentation approach is recalibrated using the local data by the maximum likelihood method. Before estimating the transferability calibration factor (Cr), three methods were used t...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given location for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, i.e., to actual safety performance, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting and evaluating cost-effective treatments. This paper presents a statistical relationship between observed crashes and simulated traffic conflicts for a range of conflict thresholds and simulation runs. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulation platform. The...
Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been... more Surrogate safety measures based on high risk vehicle interactions and traffic conflicts have been used to provide a more causal perspective on lack of safety at a given site for different road and traffic conditions. The traffic conflict approach, however, has been criticized for lacking a formal link to observational crashes, which can be viewed as being the only verification of transportation system failure from a safety perspective. Hence, a link to observed crashes provides an observational basis for the use of simulated traffic conflicts to identify sites with potential safety problems and for suggesting cost-effective treatments. This paper presents different statistical relationships between observed crashes and simulated traffic conflicts for a range of conflict thresholds. These models are then compared with conventional crash-volume prediction models. Conflicts were simulated for a sample of signalized intersections from Toronto using a VISSIM microscopic traffic simulatio...
One of the main inputs for flexible pavement design is the strength of the Unbound Granular Mater... more One of the main inputs for flexible pavement design is the strength of the Unbound Granular Materials (UGMs) and subgrade soils. In Egypt, California Bearing Ratio (CBR) is used to characterize the strength of UGMs and subgrade soils for pavement structural design. The CBR can be measured either in the laboratory or in the field. The CBR test is tedious, laborious and time consuming. This paper presents the applications of Multiple Linear Regression Analysis (MLR) and Artificial Neural Networks (ANNs) to develop CBR models through soil index properties. Database containing 120 measured CBR values along with the index properties was gathered from the quality control reports prepared at the Highway and Airport Engineering Laboratory, Mansoura University. The index properties were gradation, Atterberg limits, American Association of State Highways and Transportation Officials (AASHTO) soil classification and compaction parameters according to the modified Proctor test. CBR values ranged between 12% and 95% for unbound granular materials and subgrade soils. A CBR model was proposed as a function of Maximum Dry Density (MDD), grading modulus (GM) and percentage of retained on sieve No.10 (R#10). The GM is the summation of the passing percentage of the sieves, No. 40, No. 10 and No. 200 divided by 100. The coefficient of determination (R 2) was found to be 0.92 for MLR and 0.88 for the ANNs.
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