Metropolitan areas in nonattainment for transportation-related air pollutants rely on transportation control measures (TCMs) to reduce emissions and meet clean-air goals. However, since traditional transportationrelated air quality models use emission rates based on average speeds, only TCMs that either increase or decrease vehicle activity to speeds in which emissions are lower show reductions in output of air pollutants. In recent years, transportation air quality analysis has shifted to an activityspecific modeling approach that correlates emissions to vehicle operating mode. With an activity-specific approach, the emission reduction potential of a TCM can be evaluated by its ability to decrease time spent in modes in which emissions are disproportionately elevated. Signal timing improvements are attractive TCMs for traffic flow improvement. However, with traditional modeling, they may greatly decrease extremes in modal activity yet not show significant emission reduction if only moderate changes in average speed are realized. The benefits of using activityspecific modeling for evaluation of improved signal coordination as a TCM are described. A brief overview of the development of an activityspecific carbon monoxide emission rate model is provided, data collection for on-road vehicle activity estimates is briefly outlined, and a comparison of traditional emission modeling versus activity-specific modeling is provided to estimate the air quality benefits from improved coordination at a study intersection. Results for the study intersection indicate that more significant reductions in carbon monoxide emissions are realized using an activity-specific approach than with traditional methods.

The Small Business Liability and Brownfields Revitalization Act of 2002 reflects a continuing national commitment to redevelop and return brownfields to productive use. As brownfields are being redeveloped, there are a growing number of projects where transportation has played a critical role. Through ten case studies of contemporary brownfield redevelopments, this paper discusses the roles that transportation can play in promoting brownfields redevelopment. The cases show that transportation can either hinder or drive brownfields redevelopment. While obsolete transportation infrastructure makes brownfield corridors or areas less attractive to potential developers, transportation projects strategically designed and located to improve accessibility between brownfield corridors and major economic centers tend to drive brownfields redevelopment. Such projects can be accelerated by including them in the metropolitan and state transportation improvement programs. The cases show that municipal, county, and othe...

Dipole-allowed transitions for the inner-shell ${\mathit{C}}_{1\mathit{s}}$(2${\mathrm{\sigma }}_{\mathit{g}}$)→2${\mathrm{\Pi }}_{\mathit{u}}$ in ${\mathrm{CO}}_2$ and 2${\mathit{t}}_{1\mathit{u}}$→6${\mathit{a}}_{1\mathit{g}}$, 2${\mathit{t}}_{1\mathit{u}}$→2${\mathit{t}}_{2\mathit{g}}$, and 2${\mathit{t}}_{1\mathit{u}}$→4${\mathit{e}}_{\mathit{g}}$ in ${\mathrm{SF}}_6$; for X${\mathrm{}}^1$ ${\mathrm{\Sigma }}^{+}$→A${\mathrm{}}^1$Π and X${\mathrm{}}^1$ ${\mathrm{\Sigma }}^{+}$→C${\mathrm{}}^1$ ${\mathrm{\Sigma }}^{+}$ in CO; for excitation of ${\mathit{F}}_2$ I${\mathrm{}}^1$ ${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ and the electronic states of ${\mathrm{SO}}_2$ are investigated at small scattering angles through the generalized oscillator strength using a recent universal function [A. Z. Msezane and I. A. Sakmar, Phys. Rev. A 49, 2405 (1994)]. The results cover the electron energy between 20 eV and 2.5 keV. Good agreement with existing experimental data and calculations is obtained for the inner-shell excitation of ${\mathrm{CO}}_2$ and the 2${\mathit{t}}_{1\mathit{u}}$-6${\mathit{a}}_{1\mathit{g}}$ transition in ${\mathrm{SF}}_6$, implying that dynamic effects are unimportant at small scattering angles. The unmeasured differential cross sections (DCS’s) in the angular range of about 0°≤θ≤2° are found to contribute significantly to the integral cross sections, ranging from 40% to 69% at 300 and 500 eV in CO. The universal function approach provides an independent check of small-angle theoretical and experimental DCS’s. Given reliable small-angle DCS’s, the universal formula can be used to obtain reasonable values of optical oscillator strengths. Dynamic effects can also be investigated and are shown to be significant in the fourth positive band of CO at 500 eV, even near zero scattering angles. In contrast, dynamic effects are unimportant in the inner-shell excitation of ${\mathrm{CO}}_2$ at 1290 eV, up to large momentum-transfer-squared values, even though for the transition the first Born approximation should not be applicable. Results are presented and discussed. © 1996 The American Physical Society.