Urban arterials are landscapes that give rise to short and long-term exposures to increased transportation-related pollution. With high traffic volumes and a wide mix of road users such as those waiting for transit, pedestrians, and bicyclists, urban arterial environments are important targets for improved exposure assessment to traffic-related pollution and application of mitigation strategies. This dissertation project uses long-term roadside air quality and traffic monitoring from a signalized intersection of an urban arterial to meet the research needs of improved exposure assessment and mitigation exploration. Results thus far have shown when traffic volumes can be a reliable proxy for exposure and when this approach commonly used in exposure assessment is not warranted. On-going work is finalizing a model to predict exposure concentrations on short-term time scales, necessary for studying health impacts and exposures encountered by a variety of road users. The relationships between traffic signal settings and pollutants are being quantified to evaluate the effects of traffic signal timing on roadside air quality, a strategy often employed to reduce emissions but rarely empirically evaluated. Lastly, line source dispersion modeling predictions will be compared to measurements to assess and improve this modeling tool used in transportation and air quality planning.