Comparison of accepted gaps for different on-street parking designs

Potential problems could arise when drivers leave their parking stalls and merge into the main traffic stream. These problems could partly be attributed to finding acceptable gaps to merge into with safety and without causing undue difficulties to following vehicles. Observations from a variety of sites show different distributions of gap acceptance depending mainly upon the design and layout of parking stalls. Three chosen sites, including parallel parking and angle parking (both at 45 and 90 degrees) have been selected for this study. The surveys have been conducted using videoing techniques. The results show that the mean accepted gaps for angle parking are higher than that for parallel parking. The statistical tests indicate that there is no significant difference between the two types of angle parking. However, significant differences exist between them and those for parallel parking. This could be attributed to the type of manoeuvres associated with merging operations which are likely to involve backing-out (reversing) from the stalls in the case of angle parking. Some drivers experience difficulties with such manoeuvres which could lead into forced merging situations. This behaviour requires further investigation