Optimizing Transit Signal Priority Implementation along an Arterial

2018 ◽  
Vol 2672 (20) ◽  
pp. 215-227 ◽  
Author(s):  
Kan Wu ◽  
S. Ilgin Guler
Keyword(s):  
Travel Time ◽  
Case Studies ◽  
Signalized Intersections ◽  
Transit Signal Priority ◽  
Variational Theory ◽  
Marginal Costs ◽  
Optimization Framework ◽  
Bus Delay ◽  
Car Travel ◽  
Multiple Intersections

Transit signal priority (TSP) is a common method of providing priority to buses at signalized intersections. The implementation of TSP can affect travel time of cars traveling in the same, opposite, and cross directions. The bus delay savings and car travel-time impacts are not expected to increase linearly when considering multiple intersections along an arterial. This paper quantifies the influence of TSP on arterials with dedicated bus lanes considering an arterial-wide approach utilizing variational theory. Existing tools were modified to quantify the change in capacity along an arterial where TSP was implemented and it was shown that this effect was negligible. In addition, the bus delay savings and cross-street capacity losses were determined. Case studies provided insights into the influence of TSP among different network homogeneities and bus frequencies. Using these tools, an optimization framework was developed to determine where to implement TSP along an arterial to maximize the marginal benefits, or minimize marginal costs. In addition, a comparison of evaluating an arterial as a sum of isolated intersections as opposed to evaluating an arterial as a whole is presented. This analysis indicates the necessity of the arterial-based method in considering TSP impacts along corridors.

Does Combining Transit Signal Priority with Dedicated Bus Lanes or Queue Jump Lanes at Multiple Intersections Create Multiplier Effects?

2017 ◽  
Vol 2647 (1) ◽  
pp. 80-92 ◽  
Author(s):  
Long T. Truong ◽  
Graham Currie ◽  
Mark Wallace ◽  
Chris De Gruyter
Keyword(s):  
Public Transport ◽  
Policy Implication ◽  
Transit Signal Priority ◽  
Time And Space ◽  
Multiplier Effect ◽  
Bus Delay ◽  
Simulation Results ◽  
Multiplier Effects ◽  
Extensive Body ◽  
Multiple Intersections

An extensive body of literature deals with the design and operation of public transport (PT) priority measures. However, there is a need to understand whether providing transit signal priority with dedicated bus lanes (TSPwDBL) or transit signal priority with queue jump lanes (TSPwQJL) at multiple intersections creates a multiplier effect on PT benefits. If the benefit from providing priority together at multiple intersections is greater than the sum of benefits from providing priority separately at each of those individual intersections, a multiplier effect exists. This paper explores the effects of providing TSPwDBL or TSPwQJL at multiple intersections on bus delay savings and person delay savings. Simulation results reveal that providing TSPwDBL or TSPwQJL at multiple intersections may create a multiplier effect on one-directional bus delay savings, particularly when signal offsets provide bus progression for that direction. The multiplier effect may result in a 5% to 8% increase in bus delay savings for each additional intersection with TSPwDBL or TSPwQJL. A possible explanation is that TSPwDBL and TSPwQJL can reduce the variations in bus travel times and thus allow signal offsets—which account for bus progression—to perform even better. Furthermore, results show little evidence of the existence of a multiplier effect on person delay savings, particularly for TSPwQJL with offsets that favor person delay savings. A policy implication of these findings is that considerable PT benefits can be achieved by providing both time and space priority in combination on a corridorwide scale.

The impact of dwell time variability on transit signal priority performance

2014 ◽  
Vol 41 (2) ◽  
pp. 154-163 ◽  
Author(s):  
Mohammad S. Ghanim ◽  
Francois Dion ◽  
Ghassan Abu-Lebdeh
Keyword(s):  
Control Strategy ◽  
Dwell Time ◽  
Signalized Intersections ◽  
Time Variability ◽  
Transit Signal Priority ◽  
Operational Control ◽  
Priority Systems ◽  
Bus Delay ◽  
Transit Agencies ◽  
The Impact

Transit signal priority (TSP) is an operational control strategy that provides preferential treatments for transit vehicles at signalized intersections. Many transit agencies are currently considering the implementation of priority systems providing buses with preferential treatments at signalized intersections. While studies have demonstrated potential bus delay reductions, none has attempted to identify the problems posed by variable dwell times at bus stops. This study identifies the impacts of variable dwell times on the efficiency of transit signal priority systems. Results also show that, in general, variable dwell times negatively affect the TSP performance. However, and contrary to expectations, a number of scenarios with variable dwell times resulted in lower average bus delays than scenarios with fixed dwell times. These results are attributed to changes in progression and bus arrival patterns under variable dwell times resulting in an increasing number of buses arriving close enough to benefit from preferential treatments.

Estimating the Impacts of Bus Stops and Transit Signal Priority on Intersection Operations: Queuing and Variational Theory Approach

2017 ◽  
Vol 2622 (1) ◽  
pp. 70-83 ◽  
Author(s):  
Kan Wu ◽  
S. Ilgin Guler ◽  
Vikash V. Gayah
Keyword(s):  
Queuing Theory ◽  
Theory Approach ◽  
Transit Signal Priority ◽  
Variational Theory ◽  
Traffic Conditions ◽  
Bus Stop ◽  
Car Traffic ◽  
Trade Offs ◽  
Bus Delay ◽  
Local Agencies

Transit signal priority (TSP) can be used to improve bus operations at signalized intersections, often to the detriment of general car traffic. However, the impacts of TSP treatments applied to intersections with nearby bus stop locations are currently unknown. This paper quantifies changes in intersection capacity, car delay, and bus delay when priority is provided to buses that dwell at near- or farside bus stop locations through green extension or red truncation. Variational and kinematic wave theories are used to estimate car capacity and bus delay for oversaturated traffic conditions; queuing theory is used to estimate car and bus delays for undersaturated conditions. Numerical analyses are conducted to explore the impacts on various bus stop locations and bus dwell time durations. These results illustrate clear trade-offs between reduced bus delays and increased car delays or reduced intersection capacities that can be quantified with the proposed method. The results also reveal that the effects of TSP vary dramatically with bus dwell times for a given bus stop location. The proposed method and associated results can be used to implement TSP strategies to meet the specific needs of local agencies.

Determining Optimum Transit Signal Priority Implementation Locations on a Network

2020 ◽  
Vol 2674 (10) ◽  
pp. 387-400
Author(s):  
Murat Bayrak ◽  
S. Ilgin Guler
Keyword(s):  
Travel Time ◽  
Solution Method ◽  
Transmission Model ◽  
Transit Signal Priority ◽  
Passenger Travel ◽  
Total Travel Time ◽  
Network Operations ◽  
In Transit ◽  
Car Travel ◽  
Do So

Transit signal priority (TSP) can be used to improve bus operations at intersections. However, implementing TSP can often increase the delay of non-transit modes. Therefore, it is necessary to evaluate the effects of TSP both on car and bus operations to determine optimal locations to equip with TSP to improve network operations. To do so, the link transmission model is used to evaluate the travel times of both cars and buses on the network while accounting for dynamic queuing and queue spillover. This method is then used to evaluate different combinations of locations for TSP implementation and to determine the optimal configuration that can minimize the total travel time of network users, including bus and car passengers. The sensitivity of the proposed algorithm to demand level, changes in transit network, implementation strategy, and solution method are also evaluated. For all tested scenarios, the TSP configurations found to be optimum achieve a significant reduction of total bus passenger travel time while creating minimal effect on total car travel time. The results reveal that in general, not all intersections should be equipped with TSP, and intersections that carry high demand within a network are promising locations for TSP implementation to reduce the total travel time of network users. Additionally, it is found that the total travel time of network users can be further decreased by only activating TSP for buses with more than a certain number of on-board passengers.

A two-stage design optimization framework for multifield origami-inspired structures

2021 ◽  
pp. 1045389X2110116
Author(s):  
Wei Zhang ◽  
Saad Ahmed ◽  
Jonathan Hong ◽  
Zoubeida Ounaies ◽  
Mary Frecker
Keyword(s):  
Case Studies ◽  
Computing Time ◽  
Computational Cost ◽  
High Fidelity ◽  
Fe Model ◽  
Two Stage ◽  
Baseline Design ◽  
Optimization Framework ◽  
Highly Nonlinear ◽  
Stage 1

Different types of active materials have been used to actuate origami-inspired self-folding structures. To model the highly nonlinear deformation and material responses, as well as the coupled field equations and boundary conditions of such structures, high-fidelity models such as finite element (FE) models are needed but usually computationally expensive, which makes optimization intractable. In this paper, a computationally efficient two-stage optimization framework is developed as a systematic method for the multi-objective designs of such multifield self-folding structures where the deformations are concentrated in crease-like areas, active and passive materials are assumed to behave linearly, and low- and high-fidelity models of the structures can be developed. In Stage 1, low-fidelity models are used to determine the topology of the structure. At the end of Stage 1, a distance measure [Formula: see text] is applied as the metric to determine the best design, which then serves as the baseline design in Stage 2. In Stage 2, designs are further optimized from the baseline design with greatly reduced computing time compared to a full FEA-based topology optimization. The design framework is first described in a general formulation. To demonstrate its efficacy, this framework is implemented in two case studies, namely, a three-finger soft gripper actuated using a PVDF-based terpolymer, and a 3D multifield example actuated using both the terpolymer and a magneto-active elastomer, where the key steps are elaborated in detail, including the variable filter, metrics to select the best design, determination of design domains, and material conversion methods from low- to high-fidelity models. In this paper, analytical models and rigid body dynamic models are developed as the low-fidelity models for the terpolymer- and MAE-based actuations, respectively, and the FE model of the MAE-based actuation is generalized from previous work. Additional generalizable techniques to further reduce the computational cost are elaborated. As a result, designs with better overall performance than the baseline design were achieved at the end of Stage 2 with computing times of 15 days for the gripper and 9 days for the multifield example, which would rather be over 3 and 2 months for full FEA-based optimizations, respectively. Tradeoffs between the competing design objectives were achieved. In both case studies, the efficacy and computational efficiency of the two-stage optimization framework are successfully demonstrated.

Operational Effects of the Consolidated Intersection Design on Urban and Suburban Arterials

2018 ◽  
Vol 2672 (17) ◽  
pp. 96-107
Author(s):  
Daniel J. Cook
Keyword(s):  
Travel Time ◽  
Signalized Intersections ◽  
Signal Timing ◽  
Left Turn ◽  
Vehicle Delay ◽  
Cycle Lengths ◽  
Expected Benefits ◽  
Traffic Signal Timing ◽  
Critical Phases ◽  
Pedestrian Crossing

Along urban and suburban arterials, closely-spaced signalized intersections are commonly used to provide access to adjacent commercial developments. Often, these signalized intersections are designed to provide full access to developments on both sides of the arterial and permit through, left-turn, and right-turn movements from every intersection approach. Traffic signal timing is optimized to reduce vehicle delay or provide progression to vehicles on the arterial, or both. However, meeting both of these criteria can be cumbersome, if not impossible, under high-demand situations. This research proposes a new design that consolidates common movements at three consecutive signalized intersections into strategic fixed locations along the arterial. The consolidation of common movements allows the intersections to cycle between only two critical phases, which, in turn, promotes shorter cycle lengths, lower delay, and better progression. This research tested the consolidated intersection concept by modeling a real-world site in microsimulation software and obtaining values for delay and travel time for multiple vehicle paths along the corridor and adjacent commercial developments in both existing and proposed conditions. With the exception of unsignalized right turns at the periphery of the study area, all non-displaced routes showed a reduction in travel time and delay. Additional research is needed to understand how additional travel through the commercial developments adjacent to the arterial may effect travel time and delay. Other expected benefits of the proposed design include a major reduction in conflict points, shorter pedestrian crossing and wait times, and the opportunity to provide pedestrian refuge areas in the median.

Influencing travel behaviour

2019 ◽  
pp. 107-130
Author(s):  
Stewart Barr ◽  
John Preston
Keyword(s):  
Qualitative Study ◽  
Case Studies ◽  
Behaviour Change ◽  
Social Marketing ◽  
Quantitative Study ◽  
Behavioural Change ◽  
Travel Behaviour ◽  
Air Travel ◽  
The Other ◽  
Car Travel

As travel planning’s theoretical underpinnings have broadened from engineering and economics to embrace psychology and sociology, an emphasis has been placed on social marketing and nudge theory. It is argued that this is consistent with a neo-liberal trend towards governing from a distance. Using two case studies, one a qualitative study of reducing short-haul air travel, the other a quantitative study of attempts to reduce local car travel, it is found that actual behaviour change is limited. This seems to arise because behavioural change has been too narrowly defined and overly identified with personal choice.

San Pablo, California, Corridor Rapid Service

2017 ◽  
Vol 2647 (1) ◽  
pp. 17-25
Author(s):  
Peter Martin ◽  
Nathan Landau
Keyword(s):  
Travel Time ◽  
Lessons Learned ◽  
Bus Rapid Transit ◽  
Transit Signal Priority ◽  
Rapid Transit ◽  
East Bay ◽  
Years Of Service ◽  
Bus Service

The San Pablo, California, Rapid bus service was planned 17 years ago and was implemented 13 years ago. The Rapid service, which did not include exclusive lanes, was an upgrade of previous limited-stop bus service linking the East Bay communities of San Pablo, Richmond, El Cerrito, Albany, Berkeley, Emeryville, and Oakland. The 13 years of service provide some lessons for other communities that are considering moderate (or less than full) service upgrades to bus rapid transit. The service was quick to implement and low in cost, but it has not provided the anticipated ridership benefits. The upgrades apparently were not significant enough to attract ridership increases. The transit signal priority element was not well maintained and thus has not provided the desired travel time and reliability benefits. AC Transit—which operates the service—and the corridor communities are currently reexamining further upgrades to the service. This Rapid service is well used, but more pronounced improvements are needed to fulfill ridership potential in the corridor. The lessons learned are that minor upgrades can be easily implemented, but noticeable changes are required to achieve significant ridership gains.

Car travel time and accessibility by bus to general practitioner services: a study using patient registers and GIS

2002 ◽  
Vol 55 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Andrew Lovett ◽  
Robin Haynes ◽  
Gisela Sünnenberg ◽  
Susan Gale
Keyword(s):  
General Practitioner ◽  
Travel Time ◽  
Car Travel

scholarly journals Pedestrian Compliance at Signalized Intersections along Major Arterials

2021 ◽  
Vol 15 (1) ◽  
pp. 210-216
Author(s):  
Khaled Shaaban
Keyword(s):  
Regression Models ◽  
Middle Age ◽  
Compliance Rate ◽  
Signalized Intersections ◽  
Video Data ◽  
Logistic Regression Models ◽  
Several Variables ◽  
Pedestrian Crashes ◽  
Pedestrian Crossing ◽  
Multiple Intersections

Background: Pedestrian non-compliance at signalized crossings is unsafe and considered one of the causes of pedestrian crashes. The speed limit on most major urban roads is 60 km/hr or less. However, the speed on some urban roads is higher in some countries. In this case, the situation is more unsafe and increases the possibility of fatal injuries or fatalities in the case of a crash. Therefore, it is expected that the pedestrians will be more cautious on these roads. Aim: This study aims to explore pedestrian compliance at signalized intersections on major arterials with 80 km/hr speeds in Qatar. Methods: Video data were collected for pedestrian movements at multiple intersections. Results: The study reported a 68.1 percent compliance rate at the study locations. The results also revealed that 14.6 percent of the pedestrians crossed during the Flashing Don’t Walk interval and 17.3 percent crossed during the Steady Don’t Walk interval. These rates are considered high compared to other countries. Several variables that may influence pedestrians’ behavior were investigated. Binary and ordinal logistic regression models were developed to describe the pedestrian crossing behavior as a function of these variables. Conclusion: Male and middle-age pedestrians were more likely to cross during these two intervals. The analysis showed that female pedestrians, elder pedestrians, pedestrians crossing in groups, pedestrians waiting before crossing, and pedestrians crossing against a flow of other pedestrians are more likely to comply and cross during the Walk interval compared to other groups. Several solutions were proposed in the study to increase compliance rates.

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