Design

Going the Extra Mile: Intelligent Energy Management of Plug-In Hybrid Electric Vehicles

Kanok Boriboonsomsin, Guoyuan Wu, and Matthew Barth

Plug-in hybrid electric vehicles (PHEVs) have generated significant interest for their potential to decrease dependence on imported oil and to cut pollution and greenhouse gas emissions. While hybrid electric vehicles (HEVs) rely on their internal combustion engines to recharge their batteries, PHEVs generally have larger batteries and can be recharged by plugging into an outside electricity source, such as a standard home outlet (Figure 1). As a result, PHEVs are potentially more efficient and cleaner than HEVs, in part because more of their energy can come from clean, renewable sources.

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Two-Way Street Networks: More Efficient than Previously Thought?

Vikash V. Gayah

One-way streets in downtown areas are receiving a critical look. City officials and urban planners have started a movement to convert downtown street networks from their traditional one-way operation to two-way operation. This effort seems to be largely successful—many cities (e.g., Denver, CO; Dallas and Lubbock, TX; Tampa, FL; Des Moines, IA; Salina, KS; Kansas City, MO; Sacramento, CA) have either recently made or are in the process of making such conversions. These conversions are intended to improve vehicular access and reduce driver confusion. Many additional factors go into this decision, but the general premise is clear: travelers and residents prefer two-way streets for a variety of economic and livability reasons, while traffic engineers and transportation planners believe that one-way streets serve traffic more efficiently. Download the PDF.