Arlington County has been a national leader on bicycle infrastructure and Transportation Demand Management (TDM) since Metrorail first reached the County in the late 1970s. The County’s TDM policy was first instituted in 1990 and has been governing the County’s Site Plans and special exception buildings ever since. Included in its standard Site Plan conditions are bike parking requirements based on land use and building square footage.
It has been several years since the standard site plan condition bike parking ratios have been modified, and in that time, development in Arlington continues to pick up while community expectations for the multimodality of new projects has only increased. Arlington recently ranked 5th in the nation in a PeopleforBikes ranking of the best biking cities, due in no small part to recent infrastructure improvements for bicycling safety. It was time to re-examine these bike parking ratios and consider if they are still working for Arlington’s new residential and commercial (office) Site Plans developments.
What is a Bike Ratio, and Why Does it Matter?
Arlington’s bike ratio is currently set at 1 space per 6,000 square feet for commercial and 1 space per 2.5 units for residential Site Plans. These ratios are vital for urban planners to implement and track prior to new construction, or during renovations as an important step towards increasing ridership across the county. Studies show that having reliable end-of-trip facilities increases the likelihood of choosing to bike over other modes of transportation.
Comparing Regional and National Bike Ratios
Arlington County classifies its bike parking as follows: Class 1 (bike racks covered from the elements, inside a locked room), Class 2 (bike racks covered from elements), and Class 3 (bike racks exposed to the elements). When comparing Arlington County’s bike parking ratios for these different classes, with those of neighboring Washington-area jurisdictions, as well as the national leaders for bike infrastructure, County staff found the following:
For multi-family Class 1 residential bike parking, Arlington County requires more bike parking than the region-wide average, but less than the national leaders. For Class 2 & 3 bike parking, Arlington County requires less bike parking than the region-wide average.
For commercial Class 1 bike parking, Arlington County requires similar bike parking as the region-wide average, and as the national leaders. For Class 2/3 parking, Arlington also requires similar amounts as both the region-wide average and the national leaders.
The charts below compare Arlington’s Class 1 residential and commercial bike parking, with similar regional and national bike infrastructure leaders.
Bike Parking Occupancy Data
In addition, County staff compiled firsthand data showing the occupancy of the bike parking at over 100 Site Plan buildings throughout Arlington County, to get a sense of the utilization of the existing bike parking that has been built with the current ratios. The main takeaways from this data collection are as follows:
• County Staff found predominantly residential bike parking in Arlington to be occupied at a 91% rate for Class 1, and a 74% rate for Class 2/3, including both purely residential properties and residential/retail mixed use properties.
• County Staff found predominantly commercial bike parking to be occupied at a 27% rate for Class 1, and a 21% rate for Class 2/3, including both purely commercial properties and commercial/retail mixed use properties.
The tables below shows the data in greater detail. The data was collected by manually counting the number of bikes at each site studied, and comparing that with the number of bike parking spaces required by the building’s site plan conditions. An occupancy percentage above 100% indicates that bikes were being locked to objects that were not bike racks, such as fences and other bikes.
Additionally, this scatter plot shows the Ratio at Time of Construction vs. Bike Occupancy percentage of required spaces.
While Arlington County requires more secure residential bike parking than the regional average, it lags behind national leaders on this figure, and the high utilization rates throughout the County suggest that demand exists for more residential bike parking in Arlington. Arlington also trails other regional jurisdictions in its visitor residential bike parking requirements, although lower utilization rates suggest that supply of visitor bike parking at residential buildings is less strained.
However, it must be noted that for residential buildings, much of the occupancy figures display a high negative correlation with the bike parking ratio that was required at the time the building was built, as evidenced by the scatterplot above. Arlington’s older buildings, built when the ratio was only 1 space per 10 units (plotted at 0.1 spaces per unit in the chart above), are over-occupied, while the newer buildings, particularly those built at the current ratio of 1 space per 2.5 units, still have some excess capacity.
For both secure and visitor commercial bike parking, Arlington County’s ratio requirements are comparable to regional peers, as well as national leaders. However, supply may be currently outpacing demand for commercial bike parking in Arlington, as there is plenty of excess capacity in commercial bike parking according to our firsthand observations.
After analyzing the data, it became clear that no imminent changes were needed for Arlington’s residential or commercial bike parking ratios. They will remain at their current ratios for the time being. However, as Arlington continues to promote biking, walking, and other TDM measures, the Site Plans team hopes that bike usage rates will continue to climb. To that end, the Site Plans team hopes that this research can one day be used as a basis for potentially tweaking the ratios in the future, particularly for residential buildings. Arlington continues to aspire to be a more bike-friendly county, and if higher bike usage rates are found countywide, then higher bike parking ratios will need to follow.