Camille Kamga

Analysis of Travel Time Reliability in New York City Based on Day-of-Week and Time-of-Day Periods

Travel time reliability in New York City was analyzed with three travel time reliability measures. A classification and regression tree model was used for the analysis. Instead of analysis of conventional peak and off-peak periods, day-of-week (DOW) and time-of-day (TOD) periods were determined on the basis of each travel time reliability measure. DOW and TOD periods were identified on the basis of average travel time and each selected measure. Travel time reliability measures formulated to explain the same phenomenon classified different periods as having similar characteristics. The results agreed with the literature that reliability measures should be based on temporal periods such as DOW and TOD; however, the selection of time periods should be measure specific. The impact of New York Citys urban grid network on travel time and speed distributions is also discussed. The travel time distribution patterns reported in the literature for freeways do not exist for the city. Therefore, caution is suggested for transferring reliability measures across different network structures.

Analysis of taxi demand and supply in New York City: implications of recent taxi regulations

This paper investigates temporal and weather-related variation in taxi trips in New York City. A taxi trip data-set with 147 million records covering 10 months of activity is used. It is shown that there are substantial variations in ridership, taxi supply, trip distance, and pickup frequency for different time periods and weather conditions. These variations, in turn, cause variations in driver revenues which is one of the main measures of taxi supply–demand equilibrium. The findings are then used to discuss the anticipated impacts of two recently enacted taxi regulation changes: the first fare increase since 2006 and the E-Hail pilot program which allows taxi hailing with smart phone applications. The fare increase is estimated to cause varying levels of revenue increase for different time periods. E-Hail apps are not expected to offer considerable improvements at all times, but rather when both adequate taxi supply and demand occur simultaneously.

The Effect of Age and Gender on Motor Vehicle Driver Injury Severity at Highway-Rail Grade Crossings in the United States

INTRODUCTION Based on the Federal Railway Administration (FRA) database, there were 25,945 highway-rail crossing accidents in the United States between 2002 and 2011. With an extensive database of highway-rail grade crossing accidents in the United States from 2002 to 2011, estimation results showed that there were substantial differences across age/gender groups for drivers injury severity. METHOD The study applied an ordered probit model to explore the determinants of driver injury severity for motor vehicle drivers at highway-rail grade crossings. RESULTS The analysis found that there are important behavioral and physical differences between male and female drivers given a highway-rail grade crossing accident happened. PRACTICAL APPLICATIONS Older drivers have higher fatality probabilities when driving in open space under passive control especially during bad weather condition. Younger male drivers are found to be more likely to have severe injuries at rush hour with high vehicle speed passing unpaved highway-rail grade crossings under passive control. Synthesizing these results led to the conclusion that the primary problem with young is risk-taking and lack of vehicle handling skills. The strength of older drivers lies in their aversion to risk, but physical degradation issues which result in longer reaction/perception times and degradation in vision and hearing often counterbalance this attribute.

Virtual sensors: Web-based real-time data collection methodology for transportation operation performance analysis

Recent advances in mobile networks and an increase in the number of GPS-equipped vehicles have led to exponential growth in real-time data generation. In the past decade, several online mapping and vehicle tracking services have made their data available to third-party users. This paper explores opportunities for use of real-time traffic data provided by online services and introduces a virtual sensor methodology for collecting, storing, and processing large volumes of network-level data. To assess the validity of the collected data with the proposed methodology, this paper compares these data with data from physical loop detectors and electronic toll tag readers. Statistical analyses show a strong correlation between the travel time measurements from infrastructure-based sensors and virtual sensors. A travel time reliability analysis is then conducted with the virtual sensor data methodology. The results are promising for future research and implementation.

Costs and benefits of pneumatic collection in three specific New York City cases.

Truck-based collection of municipal solid waste imposes significant negative externalities on cities and constrains the efficiency of separate collection of recyclables and organics and of unit-price-based waste-reduction systems. In recent decades, hundreds of municipal-scale pneumatic collection systems have been installed in Europe and Asia. Relatively few prior studies have compared the economic or environmental impacts of these systems to those of truck collection. A critical factor to consider when making this comparison is the extent to which the findings reflect the specific geographic, demographic, and operational characteristics of the systems considered. This paper is based on three case studies that consider the specific characteristics of three locations, comparing pneumatic systems with conventional collection on the basis of actual waste tonnages, composition, sources, collection routes, truck trips, and facility locations. In one case, alternative upgrades to an existing pneumatic system are compared to a potential truck-collection operation. In the other cases, existing truck operations are compared to proposed pneumatic systems which, to reduce capital costs, would be installed without new trenching or tunneling through the use of existing linear infrastructure. For the two proposed retrofit pneumatic systems, up to 48,000 truck kilometers travelled would be avoided and energy use would be reduced by up to 60% at an incremental cost of up to

Highway versus urban roads: Analysis of travel time and variability patterns based on facility type

400,000 USD per year over the total operating-plus-capital cost of conventional collection. In the location where a greenfield pneumatic system is already in operation, truck collection would be both less expensive and more energy-efficient than pneumatic collection. The results demonstrate that local geographic, demographic, and operational conditions play a decisive role in determining whether pneumatic collection will reduce energy requirements, produce more or fewer greenhouse gas emissions, and cost more or less over the long-term. These findings point to the local factors that will determine the relative economic and environmental costs and benefits in specific situations.

Cycle-Length Prediction in Actuated Traffic-Signal Control Using ARIMA Model

In this study, the differences in travel time variability patterns between urban roads and highways were analyzed. For urban roads, a GPS data set that included all taxi trips in New York City was used. For highways, automatic vehicle location data from the New Jersey Turnpike were used. The turnpike was divided into two sections, urban and suburban highway, according to urbanization level, time-of-day demands, and physical roadway features. The analysis not only compared travel time patterns for highways and urban roads but also investigated travel time characteristics along the same highway facility. First, the temporal variations of travel times on both facility types were calculated and compared. Second, the travel time distributions were extracted for various time periods and compared visually to determine the distributional patterns. Finally, the relationship between the average travel time and variability was investigated. Not only did travel time patterns differ between urban roads and highways, but major differences in travel time characteristics could be observed along the same highway. Higher travel times corresponded to lower reliability on highways yet corresponded to higher reliability on urban roads. Overall, the findings suggest that attributing differences in travel time variability patterns to facility type may be an oversimplification of the phenomenon.

Difference in rural and urban driver-injury severities in highway-rail grade crossing accidents

AbstractIn urban transportation systems, the traffic signal is the main component in controlling traffic congestion. Using actuated traffic control as one of the traffic-controlling systems can cau...

Urban link travel time estimation using large-scale taxi data with partial information

Based on the Federal Railway Administration (FRA) database, there were 25,945 highway–rail crossing accidents in the United States between 2002 and 2011. With an extensive research, analysis results showed that there were substantial differences between rural and urban areas at highway–rail grade crossings. However, there is no published study specific on drivers injury severity at highway–rail grade crossings classified by area types. Using an ordered probit modelling approach, the study explores the determinants of driver-injury severity at rural highway–rail grade crossings compared with urban highway–rail grade crossings. The analysis found that motor vehicle drivers injury level at rural highway–rail grade crossing is extremely higher than urban area. Compared to collisions at urban area, collisions happened at rural area tend to result in more severe injuries. These crashes were more prevalent if vehicle drivers are driving at a high speed or the oncoming trains are high-speed. Moreover, highway–rail grade crossing accidents were more likely to occur at rural area without pavement and lighting.