Volvo Center

The Smoothing Effect of Carpool Lanes on Freeway Bottlenecks

Cassidy, Michael J
Jang, Kitae
Daganzo, Carlos F
2008

Real data show that reserving a lane for carpools on congested freeways induces a smoothing effect that is characterized by significantly higher bottleneck discharge flows (capacities) in adjacent lanes. The effect arises because disruptive vehicle lane changing diminishes in the presence of a carpool lane. The effect is reproducible across days and freeway sites: it was observed, without exception, in all cases tested.Queueing analysis shows that the effect greatly reduces the times spent by people and vehicles in queues. By ignoring the smoothing effect at one of the sites we analyzed,...

Multimodal Transport Modeling for Nairobi, Kenya: Insights and Recommendations with an Evidence-Based Model

Gonzales, Eric J.
Chavis, Celeste
Li, Yuwei
Daganzo, Carlos F.
2009

Traffic congestion is a growing problem in Nairobi, Kenya, resulting from rapidly increasing population and the crowding of motorized traffic onto a limited street network. This report includes analysis of the traffic conditions in Nairobi, the expected effects of further growth in demand, and a set of recommendations for how to improve the performance of the street network. Data describing motorized vehicle traffic was used to build a simulation model of Nairobi’s street network considering cars and matatus. This model was used to analyze traffic conditions at the city-scale under...

Spatiotemporal Effects of Segregating Different Vehicle Classes on Separate Lanes

Cassidy, Michael J.
Daganzo, Carlos F.
Jang, Kitae
2008

Spatiotemporal analysis of real freeway traffic reveals that carpool lanes are not as damaging as previously reported. To the contrary, the analysis unveils a surprising benefit of carpool lanes that should be even greater when special lanes are used to segregate very different vehicle classes, such as buses and cars. The paper pursues this finding and shows how reserving lanes on freeways and city streets for bus-use only can favorably affect not just buses, but also cars.

Structure of Competitive Transit Networks

Daganzo, Carlos F.
2009

This paper describes the network shapes and operating characteristics that allow a transit system to deliver a level of service competitive with that of the automobile. To provide exhaustive results for service regions of different sizes and demographics, the paper idealizes these regions as squares, and their possible networks with a broad and realistic family that combines the grid and the hub-and-spoke concepts. The paper also shows how to use these results to generate master plans for transit systems of real cities.The analysis reveals which network structure and technology (Bus, BRT...

Unintended Impacts of Increased Truck Loads on Pavement Supply-Chain Emissions

Sathaye, Nakul
Horvath, Arpad
Madanat, Samer
2009

In recent years, the reduction of freight truck trips has been a common policy goal. To this end, policies aimed at influencing load consolidation, load factors and increasing maximum truck weight limits have been suggested and implemented, resulting in higher gross vehicle weights. The purpose of such policies has generally been to mitigate congestion and environmental impacts. However, trucks cause most of the damage incurred by pavements. The supply chain associated with pavement maintenance and construction releases significant air emissions, raising the question of whether increased...

Environmental Life-cycle Assessment of Passenger Transportation: A Detailed Methodology for Energy, Greenhouse Gas and Criteria Pollutant Inventories of Automobiles, Buses, Light Rail, Heavy Rail and Air

Chester, Mikhail
Horvath, Arpad
2007

The passenger transportation modes of auto, bus, heavy rail, light rail and air are critical systems relied upon for business and leisure. When considering their environmental effects, most studies and policy focus on the fuel use of the vehicles, and ignore the energy and other resource inputs and environmental outputs from the life cycles of necessary infrastructures, fuels, and vehicles. The goal of this project is to develop comprehensive life-cycle assessment (LCA) models to quantify the energy inputs and emissions from autos, buses, heavy rail, light rail and air transportation in...

Unintended environmental impacts of nighttime freight logistics activities

Sathaye, Nakul
Harley, Robert
Madanat, Samer
2009

In recent years, the reduction of freight vehicle trips during peak hours has been a common policy goal. To this end, policies have been implemented to shift logistics operations to nighttime hours. The purpose of such policies has generally been to mitigate congestion and environmental impacts. However, the atmospheric boundary layer is generally more stable during the night than the day. Consequently, shifting logistics operations to the night may increase 24‐hour average concentrations of diesel exhaust pollutants in many locations. This paper presents realistic scenarios for two...

On the Design of Public Infrastructure Systems with Elastic Demand

Daganzo, Carlos F.
2012

This paper considers the optimization of public infrastructure systems, recognizing that these systems serve multiple user classes. Under the guidance of a policy-making body, the analyst chooses both the system design, including its layout and control, and the prices to be charged for the service. The goal of the optimization is to maximize society's welfare recognizing that the system's performance will in general depend on the system's demand, and vice versa. The optimization problem is first formulated in its full complexity. Under defined circumstances, the problem decomposes into...

Environmental Life-cycle Assessment of Passenger Transportation: A Detailed Methodology for Energy, Greenhouse Gas and Criteria Pollutant Inventories of Automobiles, Buses, Light Rail, Heavy Rail and Air v.2

Chester, Mikhail
Horvath, Arpad
2008

The passenger transportation modes of auto, bus, heavy rail, light rail and air are critical systems relied upon for business and leisure. When considering their environmental effects, most studies and policy focus on the fuel use of the vehicles, and ignore the energy and other resource inputs and environmental outputs from the life cycles of necessary infrastructures, fuels, and vehicles. The goal of this project is to develop comprehensive life-cycle assessment (LCA) models to quantify the energy inputs and emissions from autos, buses, heavy rail, light rail and air transportation in...

The Environmental Impacts of Electric Bikes in Chinese Cities

Cherry, Christopher
Weinert, Jonathan
Ma, Chaktan
2007

Electric bikes have captured a large share of trips in many Chinese cities. They provide high levels of mobility and use little energy, two things that Chinese cities need to optimize. However, these benefits come at a cost, particularly emissions from primarily coal power plants and increased lead waste from battery use. Chinese policy makers are struggling with developing appropriate policy that maximizes modal options and mobility and minimizes environmental impacts. Electric bikes use very little electricity and, as a result, emit low levels of pollution per vehicle (passenger)...