Using quantile smoothing splines to identify employment subcenters in a multicentric urban area

The goal of this paper is to provide a statistically based definition of employment sub centers for multicentric urban areas. In particular, we examine the sh;lpe of the employment density function using quantile smoothing splines as a nonparametric empirical specification. This approach allows inspection of the employment gradient Let the upper tail rather than the center of the employment density distribution. As a. result, our definition of employment subcenters extends previous work us it allows us to condition on distance from the central business district, relies on the extent to which a subcenter influences surrounding areas, yet still emphasizes areas' with high employment densities. (C) 2000 Academic Press.