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Speed limit(s) on west Oak Ridge Turnpike

Oak Ridge Turnpike project in 2008 -- before the trees came do

Construction has been going on so long, it's hard to remember when it started.

As Friday’s paper reported, City Council has been asked to approve new speed limits for west Oak Ridge Turnpike (SR 95) — to take effect after TDOT’s seemingly interminable widening project is finished. This portends  an end to the construction that we west end residents have endured  for the last 2-1/4 years (reportedly, TDOT has bought the new signs and is ready to put them in the ground), but I think the new limits recommended by TDOT don’t make sense, and I want to share the full story of my concerns.

Currently, city ordinances set the speed limit at 45 mph on Oak Ridge Turnpike from Illinois Avenue west to a point 200 ft west of Rarity Oaks Parkway (about 1 mile west of Wisconsin Avenue), where it increases to 55 mph. (Yes, many of us always thought the 35 mph speed limit applied west to a point somewhere around  Jefferson or Louisiana Ave., but the ordinance says the 45 mph limit starts at Illinois Ave.)

The proposal would replace that single speed limit with four different limits in  a few miles’ distance:

  • 35 mph for the first 1300 ft west of Illinois Avenue (to a point just before the first entrance to the South Hills Garden Apartments)
  • 40 mph for the next 2/3 mile or so, to a point 700 west of Jefferson Avenue
  • 50 mph for about 3-1/4 miles west of that spot, to a point 380 ft west of Oklahoma Ave.
  • 45 mph west from there to that point 200 ft west of Rarity Oaks Parkway

This proposal was discussed at a City Council work session on September 7 and was voted on at the Council meeting on September 13, so it seemed like old news to me by the time it hit the newspaper on September 17, but it’s not law until it has passed on second reading, which is scheduled for October 11. As the newspaper reported, I spoke against the change and voted against it (Anne Garcia Garland also voted against the proposal, which passed 5-2 on first reading). Here are some specific concerns I presented at the meeting:

  • Frequent changes in speed limits can be confusing to drivers, who may not see all of the signs giving notice of different limits.
  • 50 mph seems too high for safety in view of the number of businesses, residences, and street intersections along the roadway that require turning movements; plus the new sidewalks and on-street bike lanes that are being created as part of the project
  • It is particularly illogical (and confusing) to lower the speed limit (from 55 to 45 mph)  for drivers entering town from the west, then raise it again (to 50 mph) where the road enters a more congested area
  • The closeness of the road to many homes is also a concern

I pointed out that just last year the City Council had heard from residents living near Hwy 95 on Southwood and Sweetgum Lanes (west of the gatehouse, near Wisconsin Ave.) who were concerned about safety for residents and noise from the roadway, particularly after completion of the TDOT project to widen that section from 2 lanes to 4. We discussed the fact that highway noise is much greater at 55 mph than at 45. After considering the residents’ concerns and receiving a report from the city engineer on his evaluation of the situation, City Council voted to lower the speed limit near their homes from 55 mph to 45 mph.

After that action last year, it seems incongruous to be talking now about raising the speed limit on a section of the same road that is closer to more homes, has higher traffic counts, has many more turning movements associated with intersections and driveways, and will have sidewalks (adjacent to the curb) and on-highway bike lanes that will expose pedestrians to traffic. It would be inconsistent to set the limit at 50 mph on this section if the city decided that 45 was the right speed to protect the public welfare on a section with fewer potential safety and noise issues. (Not only are some residents closer to the road in this section than on Sweetgum or Southwood Lanes, but because their homes are uphill from the roadway, they receive more road noise than the downhill homes on those “S” Lanes. Also, unlike the “S” Lanes, residents in some west end neighborhoods who had long been buffered from road noise by wooded areas were not informed that they would lose those trees until after TDOT’s contractors started clearcutting.)

At first I intended to proposed an amendment to the proposal to simplify it by specifying just two speed limits: 35 mph in the areas where TDOT recommended 35 or 40, then 45 in the areas recommended as 45 or 50. However, I abandoned that idea after seeing the level of opposition by city staff. Due to past litigation about speed limits, city staff doesn’t want to change speed limits without doing an engineering evaluation first, and it has been suggested that the evaluation can’t be done until after the completed project is open to traffic. Considering that the new road configuration will be only slightly different from the 4-lane configuration that existed before the project (in spite of the long project schedule, the only substantial changes are addition of a median and those bike lanes and sidewalks), I believe that  the city has all the necessary data for an evaluation now (notably, the engineer has many years of traffic counts and knows the physical layout of the road, including intersections and driveways). Reportedly, TDOT’s recommendation is based only on physical design of the road — things like grades, curve radii, and sight distances. If TDOT engineers can make recommendations on that basis before construction is complete, surely an Oak Ridge engineer can look at that same information, along with factors like turning traffic at businesses and residential driveways, and make an even better recommendation before the reconfigured road reopens.

I think there is ample time to do an evaluation before the Oct. 11 second reading of the proposed new ordinance. However, if no new study is going to be done, I think the next best plan is simply to keep the 45 mph speed limit that’s on the books now. Accordingly, I voted against the proposed new speed limits.



  1. Ellen Smith says:

    On Facebook, Allen wrote:
    Isn’t the speed limit going east 45 until you clear the limits. As well as all other parts of town except Illinois as you exit the Pellissippi Parkway. Which is not near any housing area. Why wouldn’t the speed stay 45 until you clear Wisconsin.

    Ellen replied:
    Yes, on the east Turnpike the speed limit is 35 in the densest areas (between Illinois and Georgia Ave.) and 45 from Georgia Ave. to the city limits. It seems logical to me that the speed limit would be 45 in other “settled” areas (where the road is surrounded by homes and businesses). Speed limits aren’t determined by the city limits, though — and on Hwy 95 or 58 west you’re still in Oak Ridge all the way to the Clinch River.

    Stephany wrote:
    I certainly wish the speed limit was consistent and I would love for it to not increase until past Southwood, but that is asking too much. Thanks for taking a stand on the council.

    Sandi wrote:
    I agree. TDOT’s proposal is crazy.

    Raj asked:
    Are there any traffic analysis that recommend these speeds?

    Ellen replied:
    As I understand it, the TDOT recommendation is not based on a traffic analysis, but on the physical design of the roadway. Since the reconfigured road isn’t open to traffic yet, it’s not yet possible to do a traffic analysis on it. However, this isn’t a new road — it’s been a 4-lane road since before I moved here in 1981, and it goes through the kind of residential and commercial areas where off-highway conditions (such as pedestrians, business entrances, and driveways) typically need to be considered in defining traffic controls. A friend tells me that the city reduced the speed limit from 55 to 45 mph back in the 1970s, due to those kinds of conditions.

  2. Ellen Smith says:

    More from Facebook…

    Don wrote:
    An excellent use of Facebook!!! :-) As a resident living on a lane off Montana I am vitally interested in this subject. Roadway design as the sole basis for recommending a maximum speed is inviting trouble. We have significant local conditions that recommend a maximum of 45 for this area. The country club, shooting range and Big Turtle park to mention a few. I agree that west of the Country Club 50mph makes some sense. Recall 75% of the drivers exceed the posted limit by ten or more.

  3. Ellen Smith says:

    Still more from Facebook –>

    Stephany wrote:
    Guess what, there are still homes west of the country club. Homes with kids and pets and vehicles attempting to maneuver the turnpike traffic. Once a car careens through a yard Killing a hunting dog someone might care enough to lower the speed limit. Loss of human life wouldn’t evoke the same emotion.

    Raj wrote:
    From what I know one of the defining factors for speed is the distances between red lights. Another one is the curvature and the banking provided. I believe this back and forth in speed is to generate camera revenue (will be implemented once project is complete). I had read of a lawsuit filed where a similar jerry rigging to generate violation revenue ended in favor of the motorist. I will search to see if I can find it.

    Sandra wrote:
    Thanks for doing your homework, and mega thanks for being such a great communicator!!!!

  4. Ellen Smith says:

    Time for more Facebook input:

    Lois wrote:
    My husband & I just discussed and agree that someone is overthinking the issue. I can see leaving the limit at 35 to Jefferson. Increase the limit to 45 or 50 from Jefferson out to Southwood. They won’t have to change out THAT many signs and I’m sure TDOT can use the replaced signs on some other project. Do the speed limits fluctuate that often on Middlebrook Pike? I think that would be a good comparison.

    Ellen wrote:
    ?”Overthinking” is a good word for this situation, Lois. Thanks for suggesting it!

    I was thinking more in terms of “keep it simple” — but it’s “overthinking” that leads to overly complex solutions.

    The simplest “solution” to setting a speed limit on the west turnpike would be to simply keep the 45 mph limit that’s been on the books for more than 30 years, and I think that would work out just fine.

    To Raj: I honestly don’t think that traffic camera revenue has anything to do with this proposal. However, I do think that when speed limits change frequently, drivers are likely to perceive a “speed trap” situation.

  5. Ellen Smith says:

    More Facebook comments:

    Raj wrote:
    For goodness sake we are a scientific community and we need to base our decision on facts and comprehensive studies. There is an established scientific method to look at traffic issues like ours.

    A 4.2 miles stretch with 4 red light intersections and 4 speed changes. 50 mph = 55 to 60 mph traffic speed.

    Has any traffic engineer looked at this with simulations studied. ORNL’s NTRC has developed modeling and simulation software used around the country to study these kind of situations. I am sure they could study this for us for a small fee or even free. Maybe also an environmental impact study to look at the consequences at different speeds.
    A “Complex System” – Traffic behavior is like a coil spring. There is a startup time and distance before posted speed is reached. It is like stretching a spring and then there is braking distance and time as the spring compresses back. That causes significant noise and environmental pollution both at startup and also during braking (burnt rubber). Because of higher speed limit the amber light timing will need increasing hence running the risk of higher speed to further beat amber light. There are studies that have looked at this problem.

    There are “optimum” solutions defined by road geometry based on current traffic and projected traffic as well traffic based on system capacity of this highway system.
    One might argue that the traffic lights could be synchronized. What that would mean is longer wait time on the side roads at traffic lights. Also it will make it difficult to change lanes to get off the many closely placed exits, both for left and right turns For example entering the TPK from Montana headed west and wanting to make a left turn on one of the exits between Montana and Nebraska.See More

    Dean wrote:
    I agree with the thought that drivers will probably perceive this as a speed trap. It will also provide more fuel for those who rail on endlessly about the traffic cameras. I agree with Ellen’s vote against this since it only tends to confuse drivers. Leaving the center of a town usually involves a gradual increase in speed limits to the standard 55 mph. Increasing, followed by decreasing, followed by encreasing the speed limit does not make a lot of sense.

    Ellen wrote:
    Thanks for your professional insights, Raj. The interactions between speed limits and traffic lights are an interesting wrinkle that I hadn’t thought about. Regarding those traffic lights, they are supposed to go back to being traffic-activated once the construction project is complete — they’re temporarily operating on timers right now because the construction work kept tearing up the “loops” that detect vehicles.

  6. Ellen Smith says:

    On Facebook, Raj wrote:
    One angle that I forgot to mention earlier is the visual access i.e line of sight. Starting from Louisiana to New Bedford the TPK is serpentine. I have forgotten the numbers but I think it is 4 seconds of reaction and braking time for an average person on dry pavement condition and higher for the elderly and when it is wet. At 60 mph (typically 10 over limit) @ approximately 90 ft per second speed a typical stopping distance will be 360 to 400 feet under normal circumstances and about 600 feet if the pavement is wet. Is there a line of sight clearance to handle these speeds? I think this ought to be investigated too. Looking at satellite images on google map I do not see this is possible at several locations along the TPK. Lets remember pile on’s if a vehicle stops around the curve or is pulling out of a blind intersection.

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