Abstract

The introduction of urban rail transit and high performance/quality/capacity bus transit systems throughout the world has dramatically improved the mobility of residents of cities in which they operate. The objectives of this work are: to provide a technical resource for transit planners and designers in developing cities in their public transport capacity and performance analysis work irrespective of mode. This report recommends methods of achieving practical transit capacity during normally encountered operating conditions. Where capacity is influenced by a measure of dispersion of some characteristic such as stop dwell time or vehicle headway, this is also noted. The purpose of measuring capacity is not just to provide a measure of system capability to transport passengers but also to provide some insight into the effect of service and physical design on customer service quality. When the demand for a service exceeds its schedule design capacity, service quality deteriorates either due to overcrowding on vehicles or at station platforms or diminished ability of customers to board the next arriving transport vehicle since it is already fully loaded, increased dwell times and hence decrease revenue speeds. The importance of service quality in transit capacity analysis cannot be overstated. Transit operators should be mindful that the urban transportation marketplace is more competitive. While it might be technically possible to design a service using a loading standard of 7 or 8 passengers per square meter, a number of customers will find that level intolerable and will seek alternate means of travel including walking (in the case of short distance trips), riding with someone else, riding taxis or purchasing a motorcycle or car. Accordingly, such loading standards should be thought of as interim measures until higher capacity at lower crowding can be achieved. Document type: Book

Abstract

Under many circumstances, when providing full bus priority methods, urban transport officials have to operate buses in mixed traffic based on their road network limitations. In the case of Istanbul's Metrobus lane, for instance, when the route comes to the pre-designed Bosphorus Bridge, it has no choice but to merge with highway mixed traffic until it gets to the other side. Much has been written on the relative success of implementing Ramp Metering (RM), for example ALINEA (&lsquo Asservissement line´ aire d&rsquo entre´ e autoroutie&rsquo ) and Variable Speed Limits (VSL), two of the most widely-used &ldquo merging congestion&rdquo management strategies, in both a separate and combined manner. However, there has been no detailed study regarding the combination of these systems in the face of high bus volume. This being the case, the ultimate goal of this study is to bridge this gap by developing and proposing a combination of VSL and RM strategies in the presence of high bus volume (VSL+ALINEA/B). The proposed model has been coded using microscopic simulation software&mdash VISSIM&mdash and its vehicle actuated programming (VAP) feature referred to as VisVAP. For current traffic conditions, the proposed model is able to improve total travel time by 9.0%, lower the number of average delays of mixed traffic and buses by 29.1% and 81.5% respectively, increase average speed by 12.7%, boost bottleneck throughout by 2.8%, and lower fuel consumption, Carbon Monoxide (CO), Nitrogen Oxides (NOx), and Volatile Organic Compounds (VOC) emissions by 17.3% compared to the existing &ldquo VSL+ALINEA&rdquo model. The results of the scenario analysis confirmed that the proposed model is not only able to decrease delay times on the Metrobus system but is also able to improve the adverse effects of high bus volume when subject to adjacent mixed traffic flow along highway sections. Document type: Article

Abstract

Bus travel in mixed traffic suffers from low speed and unreliability in Seoul. The Seoul Metropolitan Government has implemented a type of bus preferential treatment at most major arterials in Seoul since 1996. That is, the reserved bus lane designated for bus use only by land and pavement markings and signs, but not by fixed physical barriers. Until 1996 bus use the most predominant travel mode in Seoul, however the share of bus trips decreased remarkably from 1990 to 1997 due to the fast growing subway supply and the increased number of private vehicles. However, after the regular bus lanes were extended, the bus service improved and thus, the buses again became the predominant travel mode since 1998. In this paper, the performance impacts of reserved bus lanes in Seoul were evaluated and several suggestions for improving the effectiveness of the bus preferential treatment are proposed. The impacts of reserved bus lanes on both bus and auto performance were primarily measured by the relative speed changes of buses and autos and the average circulation rate of bus trips. Empirical results showed that the bus lanes were successful in improving average bus performance compared with other adjacent traffic. It was confirmed that right turning movement of the buses would cause the deterioration of bus speed in the curbside bus lanes. The average circulation rate of daily bus trips during the bus operation periods was somewhat increased by the bus lane introduction. A current warrant for reserved bus lanes in Korea was reviewed, and average bus speed during peak periods was proposed as a new warrant. In order to improve the effectiveness of the reserved bus lane, the type of lane markings in reserved bus lane, enforcement strategies for illegal parking in the bus lane and FIFO service at bus stops are discussed. Document type: Article