• On-street parking significantly affects speeds. On-street parking on both sides of the <br />street visually narrows the street for those traveling along it. High 'parking densities on <br />narrow streets can dramatically reduce travel speeds. Narrow streets with low parking <br />density have an effective width similar to wide streets with high parking density. Narrow <br />streets with high parking density have the highest "traffic calming" effect. On-street <br />parking also provides a buffer between pedestrians and traffic,. <br />Because street standards are determined locally and practices have evolved over time, there are <br />great variations in residential street widths. Figure 2 depicts the range of 'neighborhood street <br />widths found in the street standards of thirty-four communities. Much of the variation has to do <br />with whether on-street parking is permitted. Nevertheless, the fact that widths vary by a factor of <br />three in cities with the same sized automobiles, fire trucks, etc. indicates that there is more <br />freedom to match street widths to the local context than most people realize. <br />• <br />Complete Streets Best Practices <br />October 2005 <br />3 <br />~;CMUi6-RA <br />302 <br />422 <br />• <br />Effect of Width: Wide, straight, long streets are an invitation to speed. <br />Frequent speed humps are needed to counteract the tendency to speed <br />on this overly wide (40ff curb-to-curb) street. <br />I. <br />