Assessing Urban Parking Challenges: Impact on Traffic Speed and Road Capacity in Nekemte City, Ethiopia

This study evaluated the impact of on-street parking on traffic speed under mixed traffic conditions in Nekemte City, Ethiopia. Data on the traffic volume, speed, and parking parameters were collected at selected mid-block locations during peak hours. The results showed that the speed of vehicles, particularly heavy vehicles and trucks, decreased significantly with increased traffic volume compared with other categories. The vehicular speed noticeably diminished as parking levels increased. A multiple linear regression model was developed using the SPSS software to analyze the percentage reduction in speed. The model indicated that for a given road width at a location with on-street parking, as parking turnover, duration, accumulation, or traffic volume increased, the percentage reduction in speed also increased. Conversely, as the road width increased, the percentage reduction in speed decreased, and vice versa, whereas the other parameters remained constant. The study concluded that the volume-speed relationship capacity of each road in the parking area and away from it could be determined, and models for percentage speed reduction could be developed using road width, parking parameters, and traffic composition. This study provides recommendations for maintaining a maximum speed reduction of 40% at selected locations for street parking based on the road width, traffic volume, parking turnover, duration, and accumulation.