I am in receipt of a copy of a memorandum from Bruce Lawrence to you dated January 31, 1989, regarding turning radius design criteria and the turning radii requirements of various vehicles. This memorandum, as I understand it, was initiated in response to a concern you have for a cul-de-sac proposed to be located near the Driftwood Motel at the terminus of River Parkway, should River Parkway be closed beyond that point. Combined with your verbal comments, I understand your concern that the designed radius is 40.5 feel, less than you consider to be adequate for the type of vehicle common to this street and the subsequent congestion and safety problems which might result from construction of the cul-de-sac.

Your concerns have been conveyed to the Mayor and it is my understand you similarly conveyed your concerns to the Public Works Committee. The radius of this cul-de-sac is physically constrained by the existence of the canal to the west and the river to the east. Nevertheless, the City Council decided at the regular City Council meeting held on February 9, 1989, to close River Parkway and proceed with the associated river beautification project. Consequently, you are hereby directed to proceed in cooperation with the Planning and Zoning Office in the construction of the cul-de-sac as per the design provided by Rod Gilchrist of that office.

Respectfully,

Chad Stanger
CS/pn
Eng/327-119C

January 31, 1989

Ed Turner:

RE: West Side Cul-de-sac Turning Radius Information

Ed,

Attached herewith is the data you asked me to gather with regard to the turning radii for various types of trucks, Rvs, Fire and emergency equipment, garbage trucks, etc. Please let me know if there is any other information that you would like to have with regard to this subject.

Sincerely,

Bruce Lawrence
Traffic Technician
Eng.file/327-119C

BL/bl

1) Recreation Vehicles (Falls RV)
Truck with 32 ft travel-trailer
Minimum turning radius - 50 ft

2) Site Bus or Tour Bus (Glen Standley - EG&G Transportation)
Site Bus or Tour Bus Vehicles
Minimum turning radius - 50 ft

3) Fire Dept Snorkle Truck (Terry Edwards - Fire Marshall)
Snorkle Truck
Minimum turning radius - 47 ft

Note: Mr. Edwards stated that they have some concern with regard to a cul-de-sac that would be farther than 150 ft from an existing cross street. A problem could arise if a vehicle accident was to take place in that segment of roadway in advance of the cul-de-sac. This would not allow fire department vehicles access from any other direction and the vehicles would have to be removed before emergency vehicles could get to the fires or injured people.

4) Sanitation Truck (Virgil Cooper - City of Idaho Falls)
Residential Sanitation Truck
Minimum turning radius - 35 ft

All of the above radii are to the gutter lip to prevent overhang of the sidewalks. It is of my opinion that we should be careful not to design a cul-de-sac that would encourage the backing of vehicles that are known to have poor visibility in an area that has a heavy concentration of pedestrian traffic of all ages.