As the transportation field grapples with the impending impacts of automated vehicles, one AV-related outcome seems clear: Highway capacity will dramatically expand. Because automatic braking systems react much faster than human drivers do, safe spacing on freeways can be reduced by about half. As a result, the current rule of thumb that a freeway lane can handle a flow of 2,000 vehicles per hour will be radically changed.
capacity
New Jersey DOT: no more roadway expansions
New Jersey’s newly appointed Department of Transportation Commissioner announced the agency will pursue a ‘fix-it-first’ mindset toward transportation spending. “The days of system expansion in New Jersey are long over, we don’t have the funds,” he said. “The focus is on the new status quo, paving, repairing deficient bridges, fixing potholes.”
Highway capacity won’t relieve congestion or lower emissions, studies conclude
A commonly cited strategy to achieve lower emissions and energy use is highway capacity expansion intended to reduce delay. But, as a new brief from UC-Davis and hosted on the Caltrans website points out, congestion relief is usually short-lived, due to “induced demand” or “induced travel.”
One-way or two-way streets more efficient? It depends on what you measure
The debate over one-way versus two-way streets has been ongoing for more than half a century in American cities. Counter to prevailing engineering wisdom, a new study finds two-way streets may be more efficient, if one is measuring getting people to their destinations.
Linking Community Visioning and Highway Capacity Planning (Strategic Highway Research Program, 2012)
This report is intended to help transportation agency practitioners assess the possibilities of community visioning efforts, identify practical steps and activities when engaging in visioning, and establish links between vision outcomes and transportation planning and …
Gas consumption down to 2000 levels
Better vehicle fuel-efficiency and moderating demand for highway travel are combining to push gasoline consumption down to its lowest levels since 2000. Despite our growing population, Americans are using less gas.The downward trend both exacerbates the erosion of fuel taxes as a source of transportation funding, but at the same time suggests that agencies may be able to economize by rethinking capacity projects.
Reinventing the urban interstate
TCRP has released a report entitled Reinventing the Urban Interstate: A New Paradigm for Multimodal Corridors. The authors present a new design framework in which multimodal corridors can take one of three forms: Transit oriented …
More roads, more traffic, really dreary news.
Many analyses of road network expansion and congestion have challenged the notion that increasing highway capacity relieves traffic. A recent study of American cities emphasizes that you can’t build your way out of congestion. The …