Street rightsizing candidates should be evaluated to determine what kinds of changes would be most effective. Our Street Selection guide immediately follows. Once selected to be rightsized, beginning the process of measuring the effort's outcomes can help support that project, and other rightsizing efforts in the project's area and beyond. Our guide to Before and After Measurements (further down this page) can help.
How do you decide which streets to prioritize for rightsizing strategies? It’s important for each community to determine its own criteria, which should reflect the realities of its streets and the people who use them. Here are a few factors to consider, which were informed by conversations with professional planners who have worked on these projects across the country.
The most successful rightsizing projects are those that are desired by a community, and that reflect their vision and values for the street. Indications of a community’s vision for a street and its surrounding area are often articulated in a master or community plan, which could include such goals as improving safety, walkability, bikeability, street life, and/or main street retail. Streets that would provide important pedestrian and bicycle connections in a community, as indicated by a bicycle or pedestrian master plan, could also be good candidates for rightsizing.
Residents or businesses may clash with the state or local transportation department in charge of their street. Community members may advocate for a street to be rightsized that the department asserts is inappropriate, or challenge the department’s assessment of their street’s suitability for rightsizing. Compromise is often possible through a lighter, quicker, cheaper trial implementation, using inexpensive paint and temporary bollards to try out the proposed configuration prior to committing with hard infrastructure.
Street Use and Traffic Volumes
Reducing the space available for motor vehicles will be more difficult if the street is a major thoroughfare for freight movement or has high vehicle volumes. For example, transportation practitioners interviewed for this project said that they typically do not promote rightsizing projects for streets with more than 20,000-25,000 average daily vehicles without exceptional circumstances and evaluation, and that streets with more than 15,000 average daily vehicles often demand an operational analysis to closely look at impacts before implementing a four to three lane conversion.
Conversely, a street with a low number of daily vehicles is often a more suitable rightsizing candidate. A street with 7,000 or 15,000 daily vehicles can generally handle a four to three lane conversion with no adverse impact on travel times or flow whatsoever, and may be pursued with relatively little study.
However, broader goals for the street should often supersede concerns about impacting traffic volumes. If there are parallel roads that are acceptable to divert traffic, and the community wants a more pedestrian-oriented street, rightsizing may be a useful option regardless of the number of daily vehicles.
Streets with high levels of traffic crashes, particularly involving pedestrians and bicyclists, are excellent candidates for rightsizing projects. Sideswipe, rear-end, and head-on crashes during turns against traffic are particularly likely to be mitigated by converting through lanes to a two-way left turn lane. Further, crash and injury severity will be reduced when vehicle speeds are slower.
Adjacent land uses help indicate the appropriateness of a street for rightsizing. Land uses that generate high numbers of pedestrians and bicyclists, such as college campuses, schools, parks, and local retail, typically suggest that a street would benefit from rightsizing improvements.
The physical layout of the street must be suitable for the changes proposed. For instance, streets with short distances between intersections, especially when they have high traffic volumes, are more difficult to remove moving lanes from without risking negative congestion. Frequency of driveways, bus stops, and space at intersections can create challenges to implementation. Further, intersections should allow turning movements for larger vehicles like emergency vehicles, buses and trucks, where necessary. Emergency vehicles can sometimes improve their travel times where there is a two-way left turn lane, if there is no raised median, because they can easily gain exclusive access to the center lane to create a passing lane. Implementing organizations may need to run traffic simulations of their proposed street changes to predict their functionality and evaluate potential turning, regulation, or signal time adjustments. Few street geometry issues will preclude the possibility of rightsizing, but rather suggest the need for careful analysis and implementation.
Of course, cost influences what kind of redesign is possible on a street. An agency may prioritize rightsizing projects on streets that are already scheduled for repaving or restriping, which can reduce the cost of changes and create the impetus for a conversation about the street's future. The cost of creating hard infrastructure, like neckdowns, can raise project costs considerably compared to simply changing the street’s striping. However, dangerous or poorly functioning streets also have significant societal and health costs that must be considered when evaluating the possibility of rightsizing a street.
Sometimes one jurisdiction, like a city, is interested in implementing a rightsizing project when another jurisdiction, like a state, is not. Depending on the road, it may be possible to transfer the right-of-way to the willing jurisdiction, as happened between the State of Florida and the City of Orlando with Edgewater Drive.
Before & After Measurements
Obtaining measurements of street conditions before and after the implementation of a rightsizing project is crucial to evaluate and communicate the project’s impacts. Before measurements can help define the problem to be solved and the suitability of the proposed solution. After measurements can help ensure that the project has achieved the desired results, and they can also inform adjustments to the project in the future. Publicizing this data can help stakeholders contextualize the impetus and results of the project, and gain public partners and support.
Most statistics are ideally measured over a multi-year period. Periods of three years before and after rightsizing a street are standard, though circumstances could dictate longer periods if a larger sample is desired or shorter periods if preliminary results are required. However, some statistics, such as safety and traffic volumes, may be aberrational immediately after rightsizing implementation as users adjust to the changes. It is also important to consider how other factors impact measurements. The expansion of a nearby parallel route, or other changes to the street network, land use, or population could have as much or more impact than the rightsizing project.
Before and after data is often more necessary for projects in areas where rightsizing has not been previously tried, or when there is considerable debate about whether the approach is appropriate for a particular street or community. The measurements should be selected based on the precipitating factors and goals of the project, and certain targets may be promised to the community as conditions for permanent implementation. Many street or area measurements will be more meaningful when referenced against rates of change in the surrounding area. Below are some best practices for gathering before and after measurements on rightsizing projects.
Measure each mode separately.
Aggregate mode volumes to obtain the total volume of daily and peak users on a given stretch of the street. Many more projects measure vehicle traffic volumes than pedestrian activity, perhaps because traffic is easier to measure, even though facilitating safe and enjoyable walking is often a goal. It may also be relevant to explore measuring volumes of specific kinds of vehicles, like trucks.
Measure volumes of negative or dangerous behavior where relevant. For instance, NYC DOT has measured the numbers of bicyclists riding on the sidewalk (Prospect Park West), as well as pedestrians walking in the street (Broadway) to help evaluate whether its street redesigns are making bicyclists and pedestrians feel more comfortable using the infrastructure designed for them. Vehicular measurements, like midblock U-turns or failure to yield, may also be relevant.
Measure by mode and aggregate across all modes.
Distinguish total injuries from serious injuries and deaths.
Consider breaking down the accidents into types, such as sideswipes or read-ends, to better predict what sorts of accidents will be reduced, as attempted in the analysis of Nebraska Avenue.
Calculate collision rates based on total “road miles” or the number of miles traveled in order to compare rates as well as the raw numbers of accidents.
Calculate the average and 85th percentile speed. Also consider calculating the percentage of cars going over the speed limit or a certain speed over the speed limit that indicates particularly dangerous driving patterns, such as drivers going 45 MPH on a 25 MPH hour.
Travel Times and Flow
Measure the point to point vehicle times to show the impact, if any, on the amount of time it takes drivers to travel between destinations.
Measure left and right hand turn times and the number of vehicles queuing.
Use "gap analysis" to record and analyze the amount of space and time between vehicles to estimate the impact of a lane reduction on issues like left hand turns and the ability of pedestrians to cross the street.
Pay special attention to public transportation operations, so that these projects do not negatively affect bus headways. Bus service data should be tracked and impacts should be mitigated if they occur.
Measure the street crossing times for pedestrians to communicate the impact of reduced distances. Evaluate with the length of crossing periods permitted by traffic signals or the ease of crossing at stop or yield signs.
Area Wide Measurements
Measure traffic counts and speeds on nearby streets that may be used as alternate routes. Often, residents are concerned about additional traffic or speeders on their blocks. In some cases, like Raymond Avenue, additional traffic calming or diversion measures may be used to ensure that there are not adverse impacts on nearby streets. In other cases, diverting some traffic to nearby parallel streets is a purposeful outcome of the project. In these cases, the volume or point-to-point measurements are most relevant for multiple streets combined. For instance, on Broadway in New York City, north of Union Square, some traffic was diverted one avenue away to Park Avenue, where there was excess capacity, which resulted in total traffic volume being maintained.
Compare parking utilization rates, turnover rates, and number of spots to indicate whether there is sufficient parking to meet demand and whether the redesign caused parking demand to increase, and by implication whether there have been desirable or undesirable parking impacts for the area’s businesses and residents.
Surveys are one way to evaluate the economic effects of a rightsizing project. Survey targets may include both local businesses and customers to gauge impacts on shopping, eating out, perceived impacts on transportation, or aesthetics etc. Edgewater Drive used an extensive survey, with positive results.
Comparing the rightsizing corridor to a reference area’s changes in vacancy rates, average rents, or sales values is another approach. This data is often particularly important because of resident and business owner concerns about property values, parking spaces, and both pedestrian and vehicular traffic.
A different approach is to look at the costs of motor vehicle crashes. This report by AAA/Cambridge Systematics asserts that traffic crashes are far more costly to local economies than congestion. It uses FHWA figures to estimate the cost of an average crash injury at $126,000 and of a death caused by motor vehicle at $6,000,000. They show the average cost of injuries and deaths per person nationally in urbanized areas as more than two and a half times as high as the average per person cost of congestion.
One example of an effort to evaluate the economic outcomes of a rightsizing project is this report on York Boulevard in Los Angeles, which is not a PPS case study.
Surveys and Public Comments
Surveys can reveal general feelings about the street, including whether the public supports specific or overall changes, suggestions for improvements, level of comfort driving, parking, walking, and biking, perceived effects on businesses, and more. An example is this survey completed by the Union Square Partnership to evaluate changes that were part of the Broadway case study.
Collect personal stories about how the previous street design impeded someone’s use of the street – for instance a crossing that a slow walker couldn't safely traverse and how the redesign has made that crossing possible – are important to putting a ‘face’ on rightsizing projects. For quality of life, community spirit, livability, or sense of safety, a person’s own story and voice may be more relevant than any numerical measure.
Finding and documenting personal stories can be as easy as interviewing a few local residents, businesses, and others in the community, working with a community organization to capture stories, or conducting a survey that asks for qualitative feedback.
Personal stories can be shared through video, photos, the media, and public engagement meetings.
Photographs & Video
A photograph can convey information with precision and profundity. Photos are cheap, quick, and effective. Photos from tall buildings or traffic lights often offer the best views, as the three-quarters perspective gives a sense of the cumulative changes and scale. Before and after photos quickly summarize the project.
Record videos to ensure that the prior conditions are accurately recalled and compared after the project is implemented. Footage of peak and lunchtime traffic, as well as left-hand turning queues, may be particularly important. Video footage is often convincing evidence for people who are skeptical of numerical measurements, or who inaccurately remember traffic conditions before implementation.
Other Potential Measurements
Pedestrian Environment: Quantify the amount of new pedestrian space available through sidewalks or plazas created, or, further, the number of other new pedestrian amenities, such as the number of seats, or quality of new street lights, etc.
Placemaking: Beyond personal stories and anecdotes, consider ways to convey that the quality of the street as a place has improved. Pedestrian measurements, particularly indications of new walking trips being generated, documentation of people lingering, and activities like phone conversations and eating outside can all help measure and convey the quality of the place.
Emissions: Evaluate the amount of greenhouse gases and pollution from vehicles that is reduced. Rightsizing projects can be undertaken as part of congestion or pollution mitigation measures by tracking the resulting mode shift, as well as the reduction in vehicular idling.
Stormwater: Measure the impact of a street redesign by quantifying the runoff diverted and/or absorbed into new landscaping or surface treatments.
Aesthetics: Communicate the changes in greenery, such as the number of new trees or pedestrian lights, and other measures that speak to the street’s aesthetic appeal.
Other Costs: Measure the cost of maintaining the street over time, since that may change.