Visibility Guidelines

Scope:

The following unobstructed triangular area will be considered to comply with the Carrollton Code of Ordinances, Title V, Chapter 53 for traffic visibility obstructions, §53.44. This applies specifically to:
1) Street/street
2) Driveway/street
3) Alley/street

Assumptions: At grade, 90° intersections

L and R = The resulting sight distances to the left and right as measured from the driver’s eye at the traffic intersection toward oncoming traffic for a distance of ‘10 x design speed limit’.

L1 and R1 = Distance along the curb line for sight line measurement.

D = Driver’s eye setback measured from the face of curb.

Intersecting Roadway Types	Sight Distance
	L and R	L1	R1	D*	D**
	(D* Driveways/ streets only; D** Alleys only)
Residential (with alley)	250'	145'	90'	15'	12'
Residential (without alley)	250'	145'	85'	15'	12'
2 Lane Undivided Collector (C2U)	300'	180'	105'	15'	12'
2 Lane Industrial	300'	180'	105'	15'	12'
4 Lane Undivided Collector (C4U)	350'	210'	110'	15'	12'
4 Lane Divided Arterial (A4D)	450'	275'	100'	15'	12'
6 Lane Divided Arterial (A6D)	500'	310'	95'	15'	12'
8 Lane Divided Arterial (A8D)	500'	310'	80'	15'	12'

   
Visibility clips shall be measured on both sides of the driveway, street or alley from face of curb.
Exceptions: 1) One-way streets 2) Non-median openings 3) Private driveways/streets

Obstructions

Assumptions: At grade, 90° intersections 

No view obstructions having a height of greater than 36” as measured from the top of curb of the adjacent streets shall be permitted within any visibility triangle area. This shall not apply to existing trees that are continually trimmed so that no branch or growth is less than 7’-0” above curb level. For a new development, proposed trees within a visibility clip shall be prohibited.