scholarly journals An investigation of the variability of start-up lost times and departure headways at signalized intersections in urban areas

2010 ◽  
Author(s):  
E. Matsoukis ◽  
St. Efstathiadis
Keyword(s):  
Urban Areas ◽  
Signalized Intersections ◽  
Start Up

Variations in Capacity at Signalized Intersections with Different Area Types

2000 ◽  
Vol 1710 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Xuewen Le ◽  
Jian Lu ◽  
Edward A. Mierzejewski ◽  
Yanhu Zhou
Keyword(s):  
Signalized Intersections ◽  
Capacity Analysis ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Central Florida ◽  
Start Up ◽  
Study Results ◽  
Lost Time

The capacity analysis procedure for signalized intersections included in the Highway Capacity Manual (HCM) needs to consider the area type of a given intersection. The area-type adjustment factor used in the procedure is based on conclusions from a limited number of studies. In addition, the procedure for using an area-type adjustment factor is not well defined in the HCM. A study undertaken in central Florida to study the effects of four different area types on the capacity of signalized intersections is summarized. These four area types include recreational, business, residential, and shopping. Study results indicated that differences in saturation headways among different area types were significant. The saturation headways observed in recreational areas were significantly higher than those in other areas for both left-turn and through movements. The through-movement saturation headways obtained in residential, shopping, and business areas were not significantly different. This study resulted in a new area-type adjustment factor of 0.92 for recreational areas, whereas the factor is 1.00 for other areas. Results in this study also indicated that the differences in start-up lost time among different area types were not significantly different. In addition, according to the results of the analysis, 75 percent of the yellow interval in undersaturated conditions and 35 percent of the yellow interval in oversaturated conditions were found to be unused and considered clearance lost time.

Extension and Application of Prosser-Dunne Model to Traffic Operation Analysis of Oversaturated, Closely Spaced Signalized Intersections

1998 ◽  
Vol 1646 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Carroll J. Messer
Keyword(s):  
Traffic Congestion ◽  
Urban Areas ◽  
Experimental Testing ◽  
Signalized Intersections ◽  
Critical Surface ◽  
Operation Analysis ◽  
Pdx Model ◽  
Computer Simulation Program ◽  
Congestion Problems ◽  
Signalized Arterials

Traffic congestion continues to have a serious impact on the productivity of the nation’s transportation system. Signalized arterials and service interchanges in urban areas serve as critical surface street facilities. These facilities often experience serious congestion problems because of high traffic demands that exceed capacity and also because of their common, closely spaced intersections and ramp terminals. Moreover, service interchanges are usually part of a signalized cross arterial and also may have short spacings to adjacent signalized intersections. Major deficiencies exist in the analysis technology and software tools available for analyzing potential traffic congestion problems at signalized arterials and service interchanges having closely spaced ramp terminals. This paper presents extensions of work originally published by Prosser and Dunne in Australia for analyzing the operational impacts of queue spillback on the capacity and delay of closely spaced signalized intersections. Coding of the described algorithm into FORTRAN was conducted, followed by experimental testing of the model using a calibrated version of the microscopic computer simulation program TRAF-NETSIM. Satisfactory comparisons were obtained between the initial version of the newly developed Prosser-Dunne Extended (PDX) model and NETSIM, but more testing and enhancement of the PDX model are recommended before implementation in existing operational software packages is considered.

Safety-Based Left-Turn Phasing Decisions for Signalized Intersections

2017 ◽  
Vol 2619 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Kiriakos Amiridis ◽  
Nikiforos Stamatiadis ◽  
Adam Kirk
Keyword(s):  
Urban Areas ◽  
Primary Objective ◽  
Signalized Intersections ◽  
Safety Performance ◽  
Signal Timing ◽  
Left Turn ◽  
Crash Data ◽  
Intersection Safety ◽  
Traffic Volumes

The efficient and safe movement of traffic at signalized intersections is the primary objective of any signal-phasing and signal-timing plan. Accommodation of left turns is more critical because of the higher need for balancing operations and safety. The objective of this study was to develop models to estimate the safety effects of the use of left-turn phasing schemes. The models were based on data from 200 intersections in urban areas in Kentucky. For each intersection, approaches with a left-turn lane were isolated and considered with their opposing through approach to examine the left-turn–related crashes. This combination of movements was considered to be one of the most dangerous in intersection safety. Hourly traffic volumes and crash data were used in the modeling approach, along with the geometry of the intersection. The models allowed for the determination of the most effective type of left-turn signalization that was based on the specific characteristics of an intersection approach. The accompanying nomographs provide an improvement over existing methods and warrants and allow for a systematic and quick evaluation of the left-turn phase to be selected. The models used the most common variables that were already known during the design phase, and they could be used to determine whether a permitted or protected-only phase would suit the intersection when safety performance was considered.

scholarly journals Development of the U-turn Accident Model at 4-Legged Signalized Intersections in Urban Areas

2014 ◽  
Vol 16 (2) ◽  
pp. 119-129
Author(s):  
JongHo Kang ◽  
KyungWhan Kim ◽  
ManBok Ha ◽  
SeongMun Kim
Keyword(s):  
Urban Areas ◽  
Signalized Intersections

Safety Performance Functions for Signalized Intersections in Large Urban Areas

2005 ◽  
Vol 1908 (1) ◽  
pp. 165-171 ◽  
Author(s):  
Craig Lyon ◽  
Anwar Haq ◽  
Bhagwant Persaud ◽  
Steven T. Kodama
Keyword(s):  
Urban Areas ◽  
Empirical Bayes ◽  
Signalized Intersections ◽  
Safety Performance ◽  
Signalized Intersection ◽  
Left Turn ◽  
Side Impacts ◽  
Recent Interest ◽  
Safety Performance Functions ◽  
Network Screening

This paper describes the development of safety performance functions (SPFs) for 1,950 urban signalized intersections on the basis of 5 years of collision data in Toronto, Ontario, Canada. Because Toronto has one of the largest known, readily accessible, urban signalized intersection databases, it was possible to develop reliable, widely applicable SPFs for different intersection classifications, collision severities, and impact types. Such a comprehensive set of SPFs is not available for urban signalized intersections from data for a single jurisdiction, despite the considerable recent interest in use of these functions for analyses related to network screening, and the development, prioritization, and evaluation of treatments. The application of a straightforward recalibration process requiring relatively little data means that the SPFs calibrated can be used by researchers and practitioners for other jurisdictions for which these functions do not exist and are unlikely to exist for some time. The value of the functions is illustrated in an application to evaluate a topical safety measure—left-turn priority treatment for which existing knowledge is on a shaky foundation. The results of this empirical Bayes evaluation show that this treatment is quite effective for reducing collisions, particularly those involving left-turn side impacts.

Nonmotorized Interference and Control Measures at Signalized Intersections in China

2003 ◽  
Vol 1846 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Heng Wei ◽  
Feng Lu ◽  
Gang Hou ◽  
Abi Mogharabi
Keyword(s):  
Urban Areas ◽  
Motor Vehicle ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Urban Transport ◽  
Control Measures ◽  
Mixed Traffic ◽  
Vehicle Traffic ◽  
Traffic Conditions ◽  
And Control

The adverse effects of bicycles and pedestrians on motor vehicle traffic in at-grade, signalized intersections under mixed-traffic conditions have been observed at several typical intersections in Beijing. Mixed bicycle and motor vehicle traffic is a major characteristic of urban transport in China and has led to serious congestion and capacity reduction in at-grade signalized intersections in urban areas. A method is presented to quantitatively measure nonmotorized effects, and values are recommended for adjusting the model to estimate the capacity of through vehicle lanes. Several temporal segregation solutions to mixed-traffic problems in at-grade signalized intersections are described that have proven cost-effective in several Chinese cities, and suggestions for their application are provided.

scholarly journals SURVIVAL OF NEW FIRMS OWNED BY NATIVES AND IMMIGRANTS IN NORWAY

2008 ◽  
Vol 13 (01) ◽  
pp. 21-38 ◽  
Author(s):  
EVGUENI VINOGRADOV ◽  
ESPEN J. ISAKSEN
Keyword(s):  
Human Capital ◽  
Survival Rate ◽  
Literature Review ◽  
Urban Areas ◽  
Relevant Literature ◽  
Survival Rates ◽  
Future Research ◽  
Business Survival ◽  
Start Up ◽  
Practical Implications

This paper investigates the survival rates of businesses founded by immigrants and natives in the context of Norway, which has not yet been explored. Based on the relevant literature review, the entrepreneur's human capital and venture's start-up characteristics were expected to explain the differences between the survival rates of businesses established by immigrants and natives. Longitudinal data on 389 firms established in 2002 were analyzed. It was revealed that the survival rate was lower for businesses established by immigrants compared to those established by natives. The analysis suggests that the relatively low survival rate of businesses established by immigrants is partly explained by the perceived novelty of the products and by the fact that immigrants are more likely to locate their businesses in urban areas. Human capital differences were not found to explain immigrant/native differences in business survival rates. Based on these results, several practical implications and suggestions for future research are offered.

Sign in / Sign up

Export Citation Format

Share Document