Access to Destinations: How Close is Close Enough? Estimating Accurate Distance Decay Functions for Multiple Modes and Different Purposes

Status:  Complete
Report Date:  04/23/2008

Summary:

The findings of the research, particularly as they relate to non-motorized modes (walking and bicycling), provide evidence that can supplement existing rules-of-thumb for pedestrian and bicyclist behavior. The findings suggest, for example, that substantial shares of pedestrian travel (perhaps one-quarter to one-third) exceed the often-cited threshold of one-quarter mile. Moreover, this finding appears to be invariant to trip purpose. Unless the segment of the population who reported these pedestrian trips are substantially different from those who either did not make utilitarian trips by the pedestrian mode or did not think to report them, this may be a welcome finding for pedestrian planning as it indicates a greater willingness to walk than is generally thought to be the case. Results for bicycle travel data reveal a substantial difference in travel distances by trip purpose. Primary activities such as work and school often involved very long bike trips (up to 20-30 KM) for those who chose this mode. In contrast, more discretionary trips (e.g. for shopping, entertainment or recreation purposes) tended to be substantially shorter in length. It would be desirable to future studies of these types of behavior to target bicycling specifically in order to provide a large enough sample to further substantiate these findings.

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