An MDR land use change would increase traffic by 177% to 246%

 Due to location and lack of public transportation, Gunbarrel residents are car-dependent. In 2015, Twin Lakes Road had 2,400 vehicles per day on average.[1] According to the Institute of Transportation Engineers (ITE) Trip Generation Manual, apartment buildings have an average daily trip (ADT) of 6.63 car trips per dwelling unit per day. The upper range for this rate is 12.5.

 The Trip Generation Manual is the same one used by Boulder County Transportation. This is the “bible” for transportation analysis. A land use change to Medium Density would result in 280 apartments. How much would this increase traffic on Twin Lakes Road?

 280 x 6.63 = 1,856 additional vehicle trips per day!   That is a 177% increase in traffic.

 According to one transportation engineer, the rate for the proposed BCHA/BVSD apartments would be closer to 12.5 because of the neighborhood’s low walkability and distance to services. Using that rate:

 280 x 12.5 = 3,500 additional vehicle trips per day!   That is a 246% increase in traffic.

 What problems will this create?

  • Twin Lakes Road has a single lane in each direction. It provides the ONLY access in and out of this proposed development and nine other neighborhoods. This traffic increase would be a hassle at best and a public safety hazard in an emergency.
  • Traffic that is already backed up for miles during rush hour will get increasingly worse (63rd & Jay; 63rd & Twin Lakes Road; 63rd & Lookout; Jay & HWY 119).
  • Many of the roads in the surrounding area are unmaintained County roads. Increasing the number of cars will further degrade the already crumbling streets and increase the expense to maintain and repair them.

Have the BVCP staff told decision makers and residents the impact that the proposed land use change will have on Gunbarrel? No, because they haven’t done a comprehensive traffic study of the subcommunity. According to the ITE, “a comprehensive traffic analysis should be completed whenever a development is expected to generate 100 or more new inbound or outbound trips during the peak hours (ITE recommended practice). Developments containing about … 220 multi-family units … would be expected to generate this level of traffic and hence, require a complete traffic analysis.” Last fall, Senior Planner Pete Fogg himself said that such an analysis was part of the criteria for the land-use change criteria of no “significant cross-jurisdictional impacts on residents, properties, or facilities.” Why was it left to us to do this analysis? For more info, visit

Cross-jurisdictional impact: A 177% to 246% increase in traffic on Twin Lakes Road and a significant increase in wear-and-tear to already deteriorating roads.



 Click document image to download the Traffic Impact whitepaper. 

Click document image to download the Traffic Impact whitepaper.