Adapted from Designing Effective Pedestrian Improvements in Business Districts, published by Project for Public Spaces, Inc.
The fundamental issue that must be addressed in the redesign of a commercial street is how to allocate its space. "Balancing" spaces is a concept that is used to describe allotting room for pedestrian needs - encouraging a lively, active public space - while at the same time maintaining appropriate vehicular space for deliveries, parking, local access, and through movement.
Balancing street spaces is both a design and a management problem, because it can be achieved by making physical changes to a street (as by creating a traffic-free mall or widening sidewalks) and by changing regulations, which control street functions. An example of the latter is a street that may be used in different ways during the course of a day: turned over to pedestrians alone from, say, noon until 2 p.m., with full vehicle access permitted the rest of the day. This flexible approach to street improvements requires active day-to-day management to ensure its success.
In order to make decisions about changing the balance of space on a street, it is important to evaluate how pedestrians and vehicles use a street, and where and when problems rise. Changes to the street can then be tailored to the type, location, and time of day when problems occur. But before embarking on a change in the balance of a given street space, decide why such a move is necessary.
Improving pedestrian flow. A common reason for changing the balance of a given street space is simply to provide more room for pedestrian movement -- to allow people to comfortably select their own walking speeds or walk in groups without bumping into other pedestrians. However, determining how wide this walking space should be is more complex than it may initially appear. Sidewalks are divided into imaginary lanes: next to the store windows is a lane about two to three feet wide which is "viewing space" used by window shoppers; at the curb, people generally allow 1.5 feet between themselves and any trees, signposts, traffic signs, etc., thus creating a second lane; in between is the "walking space." There is a minimum desirable width for this walking space - eight feet, or the amount of space necessary for two pairs of pedestrians to pass each other comfortably. There is no such rule of thumb, however, for the maximum width of a walking space; but having too much space is just as undesirable as having too little. Too much space makes a sidewalk seem "empty," because people are distributed over too large an area. This occurs in many pedestrian malls, particularly during times of day when the number of users is low.
To analyze whether pedestrian walking space is adequate, it is necessary to systematically count the number of people on the sidewalk at different locations over a period of days. It is important to realize that pedestrian volumes usually vary according to the location on the street as well as according to the time of day and day of week. Volumes may even vary within a minute because of the phenomenon known as "platooning," the surge of pedestrians caused when a light has changed at an intersection and the previously halted group of people moves down the sidewalk in a mass. Pedestrian counts should reflect such differences in time and location.
Based on these counts, it is possible to determine the levels of crowding on a sidewalk. (John Fruin developed standards for pedestrian crowding in Pedestrian Planning and Design, showing how to express pedestrian counts as a variable: "People per Foot per Minute" (PFM), or the number of people passing a given point in one minute divided by the width of the sidewalk.) PPS has found that people's perceptions of crowding are often quite different and that the best way to determine how people actually feel on commercial streets is to survey them at the same locations and at the same times at which the counts are taken.
For example, on Euclid Avenue in downtown Cleveland, PPS found that people rated the sidewalks as "very crowded" when ratings showed them to be only "constrained." Surveys thus help to determine the levels at which people feel both comfortable and uncomfortable. With this information in hand, it is possible to determine the optimum width of the pedestrian walking space in different locations. Finally, it is also important to attempt to anticipate any future increases in pedestrian flow by taking into account the effects of future major office or retail developments. A thorough evaluation of existing conditions is mandatory as a basis for making educated future projections about changes.
Providing space for pedestrian amenities. City sidewalks are not just thoroughfares for pedestrians; they function as social places where people gather to talk or meet friends, to stroll and window shop, or just to watch others pass by. A second reason to change the balance of space between pedestrians and vehicles is to provide amenities that enhance these pedestrian activities. While a sidewalk may be wide enough to accommodate pedestrian movement, it may not be wide enough to simultaneously accommodate seating, trees, bus shelters and other appropriate amenities. Once the desired width of the walking space is determined, it is necessary to consider what kinds of amenities are needed, where they are needed, and how much space they require. (Of course, the amount of space needed for amenities varies, since bus shelters occupy more ground space, for example, than benches and trees do.)
If a sidewalk can accommodate the desired amenities and the requisite pedestrian movement space, then obviously no widening is necessary. If the sidewalk is not wide enough, then either it should be expanded or the type, number and location of amenities should be modified so that the impact on pedestrian movement is minimized. If an increase in the amount of space for pedestrian amenities is needed, caution should be used in order not to provide too much space. In many cities, especially those with pedestrian malls, the amount of space devoted to amenity greatly exceeds need, and these spaces often go completely unused.
Making it easier to cross the street. Allowing people to cross the street as freely as possible is important because there are usually businesses and destinations on both sides of any commercial street. Often the width of the street and the timings of the traffic signals are designed only with the needs of vehicles-not pedestrians-in mind. For example, it is not unusual for pedestrians to have to wait for a minute or longer in order to cross the street, and then not to have sufficient time to get to the other side before the light changes. It is also not unusual for a crosswalk to be too narrow for the number of people using it, especially since the pedestrian flow consists of two platoons of pedestrians who meet in the middle of the street. A final consideration is the alignment of crosswalks, which frequently does not correspond with the routes people want to take; this increases conflicts between pedestrians and vehicles as people attempt to cross in undesignated areas.
There are essentially two types of changes that can be made to facilitate pedestrian crossing. First, changes may be made in the design of the crosswalks. They may be widened or realigned to match pedestrian routes. The actual width of a street may also be reduced through "neckdowns" or through the widening of sidewalks. A second type of change involves adjusting the traffic signals to reduce pedestrian waiting time or to increase crossing time. In cities where traffic signals' timing can vary over a day, such as those with computerized systems, it may even be possible to change these timings to accommodate periods of heavy pedestrian usage.
Pedestrian crossing patterns may be recorded through counts and time-lapse filming. Systematically counting people as they cross the street yields the number of pedestrians who are able to make it across the street within the light cycle and those who are not. This information yields the locations and times of day when crossing problems are most severe. Time-lapse filming* shows vividly how the alignment and width of crosswalks correspond to pedestrian flow patterns and, if changes are necessary, it shows where and what kind. (Such information may also be obtained through careful observation, but time-lapse film makes the patterns more evident.)
In order to balance the needs of pedestrians with those of vehicles on a street, it is necessary to understand how vehicles use a street for through movement, parking and deliveries, and how any changes made for pedestrians might affect these activities. Analysis of vehicles may also suggest how vehicular use could be controlled to increase the amount of space available to pedestrians. Eliminating on-street parking, restricting deliveries or through traffic to certain hours, or giving priority access to buses are all examples of ways that vehicular use can be modified so that it takes up less space - space that can then be made available to pedestrian needs. Such adjustments are not without benefit to vehicular use, too. Better management of vehicles can reduce traffic congestion and make a downtown more accessible and convenient, as well as more pleasant.
Observe how effectively vehicles use the street space. As with pedestrian use, vehicular use varies over the day and year; evaluating use over time can reveal when a problem exists, when it does not exist, or when one problem deserves a higher priority than another. Traffic engineers usually collect data on the number of cars that use a street over a day (by the hour) to determine if and when the number of cars exceeds a street's capacity. Time-lapse filming is a useful tool, which can provide a further dimension to this data. Time lapse filming can document the types of vehicles using a street, and whether this traffic is just passing through or has a local destination. On-street parking can be carefully studied to determine the number of cars, which use each space; this information is invaluable when deciding whether parking is serving enough people to be warranted.
Film also helps to identify specific locations where congestion and conflicts between pedestrians and vehicles occur, and which portions of a street may be underutilized. Specific lanes or portions of heavily traveled roadways often receive very little use; these areas may be reallocated to pedestrian use. Examples of time-lapse films are included in three films produced, which are available from PPS.
Examine how people use the street space. Although vehicle use should be analyzed as if there are no people in them, it is also important to look at people's use of a whole street. For example, counts may be taken of the number of people in vehicles of different kinds (buses, trucks, private cars), and his number may be compared with the number of people on the sidewalks. Data like this helps indicate how equitably space is being distributed, i.e. whether a disproportionate amount of street space is being given over to people in cars to the detriment of pedestrian activity. Comparing the number of people in buses and private cars can also suggest the impact of banning private cars from a street, and how many people would be affected. It is important to remember that adjusting vehicular use regulations will affect streets other than the one in question. If vehicles are forced to use alternative routes, an evaluation must be made to determine if those routes will bear the increased flow, and how this increased flow will affect activities along the routes.
Ultimately, the kinds of changes that can actually be made to a street are limited by the width of the street and by other physical constraints that may exist. Even if more space is desired for pedestrians, a change may not be possible unless vehicular uses can be modified in some way. A more modest approach, such as sidewalk widenings at only the most congested locations or at intersections, may be the only feasible alternative. On narrow streets (less than 40 feet from building face to building face), permanent design changes are particularly difficult to provide because space is so limited. In these instances, it may be possible to use a more flexible management approach to the street, allowing total pedestrian use during the times of day when numbers demand it and permitting required vehicular use at other times. However, a flexible street management approach is appropriate only if the density of people on foot is such that the street will not lose vitality and seem empty when vehicles are no longer present. This way to balance street space therefore becomes less desirable the wider a street is.
*For references on time-lapse filming methods, see:
Behavioral Research Methods in Environmental Design
Project for Public Spaces, Inc., Film in User Analysis (available through PPS)
William H. Whyte, The Social Life of Small Urban Spaces, Appendix (available through PPS)