Use Of Remote Sensing For Collection Of Data Elements For Linear Referencing SystemsPage 2 2. INT... more Use Of Remote Sensing For Collection Of Data Elements For Linear Referencing SystemsPage 2 2. INTRODUCTION........................................................................................................ 5 2.1 Linear Referencing.................................................................................................... 5
Rural curves are known to pose a significant safety problem, but the interaction between the driv... more Rural curves are known to pose a significant safety problem, but the interaction between the driver and roadway environment is not well understood. Thus, the objective of this research was to assess the relationship between driver behavior and characteristics, roadway factors, environmental factors, and the likelihood of roadway departures on rural two-lane curves. To accomplish this, data from the second Strategic Highway Research Program (SHRP 2) Naturalistic Driving Study (NDS) and Roadway Information Database (RID) were used to develop relationships between driver, roadway, and environmental characteristics and the risk of a roadway departure on curves. This research was tailored to address four fundamental research questions: What defines the curve area of influence? What defines normal behavior on curves? What is the relationship between driver distractions; other driver, roadway, and environmental characteristics; and risk of roadway departure? Can lane position at a particular state be predicted as a function of position in a prior state? Since four fundamental research questions were addressed, a different methodology was developed specific to each. In addition to the analytical method, the data sampling and segmentation approach, general variables considered, results, and implications are discussed for each question.
The growing number of schoolchildren being dropped off or picked up in private vehicles poses sig... more The growing number of schoolchildren being dropped off or picked up in private vehicles poses significant challenges related to student safety and traffic operations in school zones. These private vehicles must compete for space at schools with buses, bicycles, and pedestrians. This study uses on-site observations, traffic data collection, and interviews with schools, law enforcement and traffic engineers to identify transportation safety issues at elementary school sites in Iowa. Some problems frequently observed included crossing at unmarked crosswalks, unloading and loading students on the street-side, inattentive student safety patrols, and illegal parking. A range of recommendations for mitigating these problems are suggested. The recommendations include separation of transportation modes, the development of a structured arrival and dismissal protocol for parents and students, and frequent communication with parents and students about the school's expectations for the before and after school periods.
The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lan... more The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lane departures, while 40 percent of fatalities are single-vehicle run-off-road (SVROR) crashes. Addressing lane-departure crashes is therefore a priority for national, state, and local roadway agencies. Horizontal curves are of particular interest because they have been correlated with increased crash occurrence. This toolbox was developed to assist agencies address crashes at rural curves. The main objective of this toolbox is to summarize the effectiveness of various known curve countermeasures. While education, enforcement, and policy countermeasures should also be considered, they were not included given the toolbox focuses on roadway-based countermeasures. Furthermore, the toolbox is geared toward rural two-lane curves. The research team identified countermeasures based on its own research, through a survey of the literature, and through discussions with other professionals. Coverage ...
The primary objective of this toolbox is to summarize various known traffic-calming treatments an... more The primary objective of this toolbox is to summarize various known traffic-calming treatments and their effectiveness. This toolbox focuses on roadway-based treatments for speed management, particularly for rural communities with transition zones. Education, enforcement, and policy strategies should also be considered, but are not the focus of this toolbox. The research team identified treatments based on their own research, a review of the literature, and discussion with other professionals. This toolbox describes each treatment and summarizes placement, advantages, disadvantages, effectiveness, appropriateness, and cost for each treatment. The categories of treatments covered in this toolbox are as follows: horizontal physical displacement, vertical physical displacement, narrowing, surroundings, pavement markings, traffic control signs, and other strategies.
The objective of this project was to evaluate low-cost measures to reduce speeds on high-crash ho... more The objective of this project was to evaluate low-cost measures to reduce speeds on high-crash horizontal curves. The researchers evaluated two low-cost treatments in Iowa to determine their effectiveness in reducing speeds on rural two-lane roadways. This report summarizes how the research team selected sites and collected data, and the results. The team selected six sites. Retroreflective post treatments were added to existing chevrons at four sites and on-pavement curve markings were added at two sites. The researchers collected speed data before and after installation of the two treatments. The study compared several speed metrics to assess the effectiveness of the treatments. Overall, both were moderately effective in reducing speeds. The most significant impact of the treatments was in reducing the percentage of vehicles traveling over the posted or advisory speed by 5, 10, 15, or 20 or more mph. This result suggests that the treatments are most effective in reducing high-end ...
Transportation Research Record: Journal of the Transportation Research Board, 1999
New vehicle modal emissions rate models will assess emissions as a function of specific operating... more New vehicle modal emissions rate models will assess emissions as a function of specific operating mode or engine load surrogates. These new models require that vehicle activity be input by fraction of time spent in different operating modes. However, the ability to realistically model onroad modal vehicle activity currently limits the implementation of these models. Few data on how vehicles operate in a real-world setting exist. Simulation models offer attractive advantages for modal modeling. They are readily available and generally can be used with both simple and detailed data input. Simulation models were developed to model the impacts of signal timing, incidents, or design features on traffic flow and perform well for these applications. However, simulation models, such as CORSIM, use theoretical profiles of vehicle acceleration and speed relationships that have not been validated in the field. To determine the feasibility of using simulation models to predict on-road speedacce...
Transportation Research Record: Journal of the Transportation Research Board, 2012
Pavement edge drop-off can be a serious safety concern when a vehicle leaves the paved 18 roadway... more Pavement edge drop-off can be a serious safety concern when a vehicle leaves the paved 18 roadway surface and encounters a significant vertical elevation difference between the paved 19 roadway and the adjacent unpaved shoulder. Edge drop-offs are potential ...
Fuel costs are a significant portion of transit agency budgets. Hybrid buses offer an attractive ... more Fuel costs are a significant portion of transit agency budgets. Hybrid buses offer an attractive option and have the potential to reduce operating costs for agencies significantly. Hybrid technology has been available in the transit market for some time. As of 2009, there are more than 1,200 hybrid buses in regular service in North America in more than 40 transit agencies (Transport Canada 2011). The majority of these buses are regular 40 ft buses, although some smaller (20 ft) shuttle buses and larger articulated (60 ft) buses are also in service. The transit agency in New York, New York has approximately 1,000 hybrid vehicles as of 2009 (Maynard 2009) and Toronto, Canada has approximately 33 percent (Transport Canada 2011). The main reasons agencies consider hybrid transit vehicles are fuel savings and reduced emissions. Hybrid electric buses offer an attractive option and have the potential to reduce operating costs for transit agencies significantly. Wayne et al. (2009) estimate...
A number of traffic-calming devices were evaluated to determine their effectiveness in reducing s... more A number of traffic-calming devices were evaluated to determine their effectiveness in reducing speeds along the main road through a small rural community. Five different treatments were selected and installed in six rural Iowa communities. This tech brief highlights use of temporary curbing to create center islands. Pneumatic road tubes were used to collect speed and volume data before and after installation of the rural traffic calming treatments. Data were typically collected for 48 hours on a Monday through Friday under mostly dry weather conditions. Speeds decreased at two sites with decreases up to 2.2 mph in mean speed and up to 3 mph in 85th percentile speed. The fraction of vehicles traveling 5 or more mph over the posted speed limit decreased by 29 percent and the fraction of vehicles traveling 10 or more mph over decreased by 29 to 46 percent. A large decrease (up to 71 percent) resulted in the fraction of vehicles traveling 15 or more mph over the posted speed limit. The...
A number of traffic-calming devices were evaluated to determine their effectiveness in reducing s... more A number of traffic-calming devices were evaluated to determine their effectiveness in reducing speeds along the main road through a small rural community. Five different treatments were selected and installed in six rural Iowa communities. This tech brief highlights use of transverse speed bars. Pneumatic road tubes were used to collect speed and volume data before and after installation of the rural traffic-calming treatments. Data were typically collected for 48 hours on a Monday through Friday under mostly dry weather conditions. Typical speed statistics, such as change in average speed, were calculated for each location where data were collected. Speeds decreased at two of the three sites with decreases of 1 mph in mean and 85th percentile speeds. The fraction of vehicles traveling 5 or more mph over the posted speed limit decreased by about 8 percent and the fraction of vehicles traveling 10 or more mph over decreased by 12 percent for both sites. A large decrease resulted in ...
The Institute of Transportation Engineers Traffic Engineering Council technical committee conduct... more The Institute of Transportation Engineers Traffic Engineering Council technical committee conducted a survey on school-related traffic control devices in early 2007. The 37-question survey gathered information on: the state-of-the-practice for school speed zones, signing and markings for schools, and engineering judgment on when to install a school speed zone. A total of 168 participants provided responses and this paper contains a summary of the findings for each question.
Background Small rural communities often lack the expertise and resources necessary to address sp... more Background Small rural communities often lack the expertise and resources necessary to address speeding and the persistent challenge of slowing high-speed through traffic. The entrances to communities are especially problematic given that drivers must transition from a high-speed, often-rural roadway setting to a low-speed community setting. The rural roadway provides high-speed mobility outside the community, yet the same road within town provides local access and accommodates pedestrians of all ages, on-street parking, bicycles, and other features unique to the character of a small community. Drivers who have been traveling for some distance on the high-speed road, and are traveling through the community, may not receive the appropriate clues that the character of the roadway is changing and may not adjust their speeds appropriately. Addressing speeding issues is an even greater challenge given that smaller communities typically lack engineering staff and resources, which can lead
About 56% of traffic fatalities in the US are roadway departures. In 2013, this represented 18,25... more About 56% of traffic fatalities in the US are roadway departures. In 2013, this represented 18,257 fatalities (FHWA 2014). One contributor to roadway departure crashes is the presence of pavement edge drop-off, which is a vertical elevation difference between two adjacent roadway surfaces. Edge dropoffs are potential safety hazards because significant vertical differences between surfaces can reduce vehicle stability and impede the driver’s ability to handle their vehicle (Ivey et al. 1984). A typical pavement edge drop-off-related crash occurs when the driver attempts an immediate return to the roadway and tire scrubbing occurs.
Use Of Remote Sensing For Collection Of Data Elements For Linear Referencing SystemsPage 2 2. INT... more Use Of Remote Sensing For Collection Of Data Elements For Linear Referencing SystemsPage 2 2. INTRODUCTION........................................................................................................ 5 2.1 Linear Referencing.................................................................................................... 5
Rural curves are known to pose a significant safety problem, but the interaction between the driv... more Rural curves are known to pose a significant safety problem, but the interaction between the driver and roadway environment is not well understood. Thus, the objective of this research was to assess the relationship between driver behavior and characteristics, roadway factors, environmental factors, and the likelihood of roadway departures on rural two-lane curves. To accomplish this, data from the second Strategic Highway Research Program (SHRP 2) Naturalistic Driving Study (NDS) and Roadway Information Database (RID) were used to develop relationships between driver, roadway, and environmental characteristics and the risk of a roadway departure on curves. This research was tailored to address four fundamental research questions: What defines the curve area of influence? What defines normal behavior on curves? What is the relationship between driver distractions; other driver, roadway, and environmental characteristics; and risk of roadway departure? Can lane position at a particular state be predicted as a function of position in a prior state? Since four fundamental research questions were addressed, a different methodology was developed specific to each. In addition to the analytical method, the data sampling and segmentation approach, general variables considered, results, and implications are discussed for each question.
The growing number of schoolchildren being dropped off or picked up in private vehicles poses sig... more The growing number of schoolchildren being dropped off or picked up in private vehicles poses significant challenges related to student safety and traffic operations in school zones. These private vehicles must compete for space at schools with buses, bicycles, and pedestrians. This study uses on-site observations, traffic data collection, and interviews with schools, law enforcement and traffic engineers to identify transportation safety issues at elementary school sites in Iowa. Some problems frequently observed included crossing at unmarked crosswalks, unloading and loading students on the street-side, inattentive student safety patrols, and illegal parking. A range of recommendations for mitigating these problems are suggested. The recommendations include separation of transportation modes, the development of a structured arrival and dismissal protocol for parents and students, and frequent communication with parents and students about the school's expectations for the before and after school periods.
The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lan... more The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lane departures, while 40 percent of fatalities are single-vehicle run-off-road (SVROR) crashes. Addressing lane-departure crashes is therefore a priority for national, state, and local roadway agencies. Horizontal curves are of particular interest because they have been correlated with increased crash occurrence. This toolbox was developed to assist agencies address crashes at rural curves. The main objective of this toolbox is to summarize the effectiveness of various known curve countermeasures. While education, enforcement, and policy countermeasures should also be considered, they were not included given the toolbox focuses on roadway-based countermeasures. Furthermore, the toolbox is geared toward rural two-lane curves. The research team identified countermeasures based on its own research, through a survey of the literature, and through discussions with other professionals. Coverage ...
The primary objective of this toolbox is to summarize various known traffic-calming treatments an... more The primary objective of this toolbox is to summarize various known traffic-calming treatments and their effectiveness. This toolbox focuses on roadway-based treatments for speed management, particularly for rural communities with transition zones. Education, enforcement, and policy strategies should also be considered, but are not the focus of this toolbox. The research team identified treatments based on their own research, a review of the literature, and discussion with other professionals. This toolbox describes each treatment and summarizes placement, advantages, disadvantages, effectiveness, appropriateness, and cost for each treatment. The categories of treatments covered in this toolbox are as follows: horizontal physical displacement, vertical physical displacement, narrowing, surroundings, pavement markings, traffic control signs, and other strategies.
The objective of this project was to evaluate low-cost measures to reduce speeds on high-crash ho... more The objective of this project was to evaluate low-cost measures to reduce speeds on high-crash horizontal curves. The researchers evaluated two low-cost treatments in Iowa to determine their effectiveness in reducing speeds on rural two-lane roadways. This report summarizes how the research team selected sites and collected data, and the results. The team selected six sites. Retroreflective post treatments were added to existing chevrons at four sites and on-pavement curve markings were added at two sites. The researchers collected speed data before and after installation of the two treatments. The study compared several speed metrics to assess the effectiveness of the treatments. Overall, both were moderately effective in reducing speeds. The most significant impact of the treatments was in reducing the percentage of vehicles traveling over the posted or advisory speed by 5, 10, 15, or 20 or more mph. This result suggests that the treatments are most effective in reducing high-end ...
Transportation Research Record: Journal of the Transportation Research Board, 1999
New vehicle modal emissions rate models will assess emissions as a function of specific operating... more New vehicle modal emissions rate models will assess emissions as a function of specific operating mode or engine load surrogates. These new models require that vehicle activity be input by fraction of time spent in different operating modes. However, the ability to realistically model onroad modal vehicle activity currently limits the implementation of these models. Few data on how vehicles operate in a real-world setting exist. Simulation models offer attractive advantages for modal modeling. They are readily available and generally can be used with both simple and detailed data input. Simulation models were developed to model the impacts of signal timing, incidents, or design features on traffic flow and perform well for these applications. However, simulation models, such as CORSIM, use theoretical profiles of vehicle acceleration and speed relationships that have not been validated in the field. To determine the feasibility of using simulation models to predict on-road speedacce...
Transportation Research Record: Journal of the Transportation Research Board, 2012
Pavement edge drop-off can be a serious safety concern when a vehicle leaves the paved 18 roadway... more Pavement edge drop-off can be a serious safety concern when a vehicle leaves the paved 18 roadway surface and encounters a significant vertical elevation difference between the paved 19 roadway and the adjacent unpaved shoulder. Edge drop-offs are potential ...
Fuel costs are a significant portion of transit agency budgets. Hybrid buses offer an attractive ... more Fuel costs are a significant portion of transit agency budgets. Hybrid buses offer an attractive option and have the potential to reduce operating costs for agencies significantly. Hybrid technology has been available in the transit market for some time. As of 2009, there are more than 1,200 hybrid buses in regular service in North America in more than 40 transit agencies (Transport Canada 2011). The majority of these buses are regular 40 ft buses, although some smaller (20 ft) shuttle buses and larger articulated (60 ft) buses are also in service. The transit agency in New York, New York has approximately 1,000 hybrid vehicles as of 2009 (Maynard 2009) and Toronto, Canada has approximately 33 percent (Transport Canada 2011). The main reasons agencies consider hybrid transit vehicles are fuel savings and reduced emissions. Hybrid electric buses offer an attractive option and have the potential to reduce operating costs for transit agencies significantly. Wayne et al. (2009) estimate...
A number of traffic-calming devices were evaluated to determine their effectiveness in reducing s... more A number of traffic-calming devices were evaluated to determine their effectiveness in reducing speeds along the main road through a small rural community. Five different treatments were selected and installed in six rural Iowa communities. This tech brief highlights use of temporary curbing to create center islands. Pneumatic road tubes were used to collect speed and volume data before and after installation of the rural traffic calming treatments. Data were typically collected for 48 hours on a Monday through Friday under mostly dry weather conditions. Speeds decreased at two sites with decreases up to 2.2 mph in mean speed and up to 3 mph in 85th percentile speed. The fraction of vehicles traveling 5 or more mph over the posted speed limit decreased by 29 percent and the fraction of vehicles traveling 10 or more mph over decreased by 29 to 46 percent. A large decrease (up to 71 percent) resulted in the fraction of vehicles traveling 15 or more mph over the posted speed limit. The...
A number of traffic-calming devices were evaluated to determine their effectiveness in reducing s... more A number of traffic-calming devices were evaluated to determine their effectiveness in reducing speeds along the main road through a small rural community. Five different treatments were selected and installed in six rural Iowa communities. This tech brief highlights use of transverse speed bars. Pneumatic road tubes were used to collect speed and volume data before and after installation of the rural traffic-calming treatments. Data were typically collected for 48 hours on a Monday through Friday under mostly dry weather conditions. Typical speed statistics, such as change in average speed, were calculated for each location where data were collected. Speeds decreased at two of the three sites with decreases of 1 mph in mean and 85th percentile speeds. The fraction of vehicles traveling 5 or more mph over the posted speed limit decreased by about 8 percent and the fraction of vehicles traveling 10 or more mph over decreased by 12 percent for both sites. A large decrease resulted in ...
The Institute of Transportation Engineers Traffic Engineering Council technical committee conduct... more The Institute of Transportation Engineers Traffic Engineering Council technical committee conducted a survey on school-related traffic control devices in early 2007. The 37-question survey gathered information on: the state-of-the-practice for school speed zones, signing and markings for schools, and engineering judgment on when to install a school speed zone. A total of 168 participants provided responses and this paper contains a summary of the findings for each question.
Background Small rural communities often lack the expertise and resources necessary to address sp... more Background Small rural communities often lack the expertise and resources necessary to address speeding and the persistent challenge of slowing high-speed through traffic. The entrances to communities are especially problematic given that drivers must transition from a high-speed, often-rural roadway setting to a low-speed community setting. The rural roadway provides high-speed mobility outside the community, yet the same road within town provides local access and accommodates pedestrians of all ages, on-street parking, bicycles, and other features unique to the character of a small community. Drivers who have been traveling for some distance on the high-speed road, and are traveling through the community, may not receive the appropriate clues that the character of the roadway is changing and may not adjust their speeds appropriately. Addressing speeding issues is an even greater challenge given that smaller communities typically lack engineering staff and resources, which can lead
About 56% of traffic fatalities in the US are roadway departures. In 2013, this represented 18,25... more About 56% of traffic fatalities in the US are roadway departures. In 2013, this represented 18,257 fatalities (FHWA 2014). One contributor to roadway departure crashes is the presence of pavement edge drop-off, which is a vertical elevation difference between two adjacent roadway surfaces. Edge dropoffs are potential safety hazards because significant vertical differences between surfaces can reduce vehicle stability and impede the driver’s ability to handle their vehicle (Ivey et al. 1984). A typical pavement edge drop-off-related crash occurs when the driver attempts an immediate return to the roadway and tire scrubbing occurs.
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