Road Diets: Don’t Try This At Home – Anne Wallace Responds


In response to last week’s article regarding road diets, I received a lengthy and thoughtful response from Anne Wallace, Deputy Director of the Office of Redevelopment for the city of Knoxville and the project manager for the Cumberland Avenue Corridor Plan. She corrected a couple of errors I made and, generally, gave a fuller picture of the details that impact a project of that size. She explained the twelve-foot lanes and lack of bike lanes on Cumberland and, I felt, made an excellent point of the differences between the simple examples of a road diet in the Jeff Speck video I had included and the complicated situation involving a road with so many businesses and curb cuts already present.

I wanted our larger community to benefit from her detailed explanation, so I asked if I could publish her work as an article. She agreed and here’s what she had to say. I’ve very lightly edited the piece, but the words are all hers:



There was an extensive public process that went into the development of the adopted plan, A History of Connection, Cumberland Avenue Corridor Plan, 2007, a copy of which is available at, look in the links on the right side. You’ll note on page 4-3 the goals of the road diet for Cumberland were to: 1) Provide pedestrian amenities along Cumberland, 2) Encourage new development to build to the right of way, 3)Provide a left turn lane, 4) Minimize curb-cuts along Cumberland Avenue, and 5) Improve pedestrian connections.

Bike lanes were not mentioned. I was not a part of that planning process, so I cannot speak to the omission other than to note it and that there were several changes from the concept plan to implementation. The concept plan assumed the closure of all the curb cuts on Cumberland Avenue  (there are more than 30 curb cuts, even with some properties changing their development pattern with the adoption of the Form Based Code) and there are four north/south streets that do not align in the six block length of the corridor.

The turning volumes on this corridor are enormous (both left and right turns before construction started and right turns into driveways since the start of construction). A majority of businesses along the corridor derive the majority of their sales from drive-in or drive-through traffic (for example, when negotiating the right of way process, McDonald’s noted that 60-80% of their business was from drive-in/drive-through traffic…it’s similar for Wendy’s, FedEx Kinko’s, Krystal, Zaxby’s, CookOut, Starbucks, the Shell gas station and others).

Recognizing that we were planning to use Federal Funds through TDOT, we were told clearly that we would have to comply with the Uniform Relocation Act ( and pay for the curb cuts to be closed since they were considered assets of the business. In the examples listed above, that meant we would be buying entire businesses to close the drive way curb cuts, obviously with the funding constraints and the desire to allow existing businesses to remain on the  corridor that was infeasible. So we had to look at another way to address safety for ALL modes of transportation. We held a meeting in April of 2010 to look at what options were available to address this conflict and we presented 3 options with alternates to the public and received feedback that supported the wider sidewalks and median.

Unfortunately, what was discovered after the public meeting, during the course of detailed design, was that the actual right of way was smaller than the assumed 70’ typical section from the planning process. It was typically 65’ and in some locations less. Therefore we had to find ways to still meet the stated goals with less flexibility and fewer options; this led us to the one lane each direction with a median to direct left turn movements at side streets. Additionally, because we were using Federal Funding a minimum lane width of 12’ was established by TDOT.

Subsequently, we were able to address significant safety concerns for both pedestrians and motorists by utilizing the median through the corridor in order to reduce left turns to intersections and shortening crossing distances by having refuges in the medians for the non-signalized crosswalks. We had to get very creative to find locations for transit to stop within the travel lane and still allow for traffic to move around the impediment during loading and unloading – we ended up taking space from the median to accommodate this.

However, by no means were we ignoring bicyclists throughout this process. We stepped back and looked at the whole corridor plan area – it includes Lake and White Avenues which function as one-way pairs to the north and south of Cumberland Avenue. These are local roads. Cumberland was formerly a state highway and carries more than 34,000 average daily trips while Lake and White Avenue are local roads and carry less than 10,000 average daily trips. There is also on street parking on both sides of the roadway on Lake and White Avenue which tends to cause drivers to drive at slower rates of speed.

Additionally, White Avenue eastbound has less grade over the same distance as Cumberland, making it safer for cyclist to “climb” than using Cumberland. So, given these great resources one block off of Cumberland, we changed all the side streets (except 22nd south of Cumberland) to two way traffic so cyclists could access anywhere on Cumberland without having to mix with 3 times more vehicular traffic. No, we did not put bike lanes on Cumberland, but we have made accommodations for any cyclist to safely access locations and businesses on Cumberland Avenue by using the shared lanes on Lake and White Avenues and connecting by the side streets to Cumberland. The image below shows the shared lane markings on White Avenue.

Bicycle Markings on White Avenue

As noted above, the vehicular lanes were not made wider for bike/car sharing, 12’ was the minimum required lane width for the roadway. That may very well not be ideal in an urban corridor, however, it was a requirement of our funding source. I will also note that given the truck traffic on Cumberland Avenue (you should join us for a walk through sometime because you would be surprised at the amount of truck traffic) having the 12’ lane requirement will make it less likely for a trucks rear end to roll over the curb and onto the sidewalk while making a right turn.

On another point, there are studies that show having vertical elements adjacent to the roadway, makes drivers more aware of their speed because of the vertical elements registering in their peripheral vision – so our inclusion of street trees and lights at regular intervals along the roadway will help to moderate traffic speeds and increase safety. (See for examples:,

As a personal observation, adding an additional 4’ or 5’ of roadway width for a bike lane may or may not improve bike safety as it pushes the vertical elements along the roadway further from the driver and they feel more comfortable going faster; it can also give cyclist the false sense of security when there are so many curb cuts and turn movements crossing the bike lane path.

With regard to Jeff Speck’s video – I would note that there might be one drive way curb cut represented in the entire block on one side of the street, and his simulation does not show any turn movement across the bike lane – if only we were so lucky on Cumberland! Having a car turning across the bike lane at multiple points within the span of one block is a significant conflict.

To one of the comments on your post about bicyclists using the sidewalk, while it may indeed occur in the future on Cumberland, there are two points to consider: 1) Tennessee state law allows for bikes to use sidewalks – if that is not preferred, efforts should be made to change state law; and 2) it is more likely in a bicycle/pedestrian conflict for both entities to survive than it is in a bicycle/vehicle conflict.

Additionally, we did not move utilities underground – we saved millions, literally, by coordinating with KUB and putting the overhead utilities on new poles within the alley where there were existing overhead utilities already present. We removed outdated wooden poles and installed stronger ductile iron poles painted black to reduce impact to the visual environment.