Modeling and analyzing the impact of on-street parking on traffic flow: a study of the main highway in Debre Markos Town, Ethiopia

Insufficient parking has emerged as a critical global transportation concern, particularly in central business districts, leading to congestion in urban transport networks with significant social, economic, and environmental implications. In Debre Markos city, the demand for taxis and travel is swiftly rising due to population growth. However, existing road facilities are inadequate, reducing road capacity, mobility, and exacerbating traffic congestion. On-street parking, encompassing parking occupancy, double parking, differences in peak hours between restaurant activity and passing traffic, lack of driver discipline, and the reduced maneuverability of older vehicles, all contribute to narrowing the available road width, thus impeding traffic flow. This study aims to bridge this knowledge gap by investigating the traffic congestion caused by on-street parking and its impacts on traffic flow. Study results indicate that on-street parking significantly reduces road capacity by 24.1% due to legal parking activities and an additional 25.89% due to illegal double parking. Removing on-street parking could enhance road capacity by 49.9% and reduce travel time by 36%. Additionally, the model reveals a strong relationship between on-street parking and the delay of vehicle movement toward parking locations, with each increase in parking occupancy decreasing average travel speed by 0.03 km/h. This study emphasizes the necessity for proactive policies to address parking issues and uphold urban street service levels amid increasing traffic demands. Local authorities can use the model as a guide for implementing parking prohibition policies, including utilizing dead-end roads for short-term parking, enhance enforcement of parking regulations, integrate parking management with urban planning, and implementing parking management measures to alleviate congestion.