RP-8 Design Criteria

The Illuminating Engineering Society (IES) of North America provides recommended roadway design criteria in its document called Recommended Practice 8, Roadway Lighting (RP-8). RP-8-00, published in 2000 and reaffirmed in 2005, contains the tables shown below. All design criteria for Illuminance and Luminance are given in metric units. For convenience, lux and approximate footcandle levels are quoted in the Illuminance table. 

Illuminance Method - Recommended Values

Roadway & Pedestrian Conflict Area

Pavement Classification

(Minimum Maintained Average Values)

Uniformity Ratio

Eavg /Emin 

Veiling Luminance Ratio

Lv,max/Lavg

 

Road

Pedestrian Conflict Area

R1

lux/fc

R2 & R3

lux/fc

R4

lux/fc

Freeway Class A

 

6.0 / 0.6

9.0 / 0.9

8.0 / 0.8

3.0

0.3  

Freeway Class B

 

4.0 / 0.4

6.0 / 0.6

5.0 / 0.5

3.0

0.3  

Expressway

High

10.0 / 1.0

14.0 / 1.4

13.0 / 1.3

3.0

0.3  

Medium

8.0 / 0.8

12.0 / 1.2

10.0 / 1.0

3.0

0.3  

Low

6.0 / 0.6

9.0 / 0.9

8.0 / 0.8

3.0

0.3  

Major

High

12.0 / 1.2

17.0 / 1.7

15.0 / 1.5

3.0

0.3  

Medium

9.0 / 0.9

13.0 / 1.3

11.0 / 1.1

3.0

0.3  

Low

6.0 / 0.6

9.0 / 0.9

8.0 / 0.8

3.0

0.3  

Collector

High

8.0 / 0.8

12.0 / 1.2

10.0 / 1.0

4.0

0.4  

Medium

6.0 / 0.6

9.0 / 0.9

8.0 / 0.8

4.0

0.4  

Low

4.0 / 0.4

6.0 / 0.6

5.0 / 0.5

4.0

0.4  

Local

High

6.0 / 0.6

9.0 / 0.9

8.0 / 0.8

6.0

0.4  

Medium

5.0 / 0.5

7.0 / 0.7

6.0 / 0.6

6.0

0.4  

Low

3.0 / 0.3

4.0 / 0.4

4.0 / 0.4

6.0

0.4  

 

Luminance Method - Recommended Values

Roadway & Pedestrian Conflict Area

Ave. Luminance

Lavg (cd/m2)

Uniformity Ratio

Lavg /Lmin 

Uniformity Ratio

Lmax /Lmin 

Veiling Luminance Ratio

Lv,max /Lavg 

Road

Pedestrian Conflict Area

Freeway Class A

 

0.6

3.5

6.0

0.3

Freeway Class B

 

0.4

3.5

6.0

0.3

Expressway

High

1.0

3.0

5.0

0.3

Medium

0.8

3.0

5.0

0.3

Low

0.6

3.5

6.0

0.3

Major

High

1.2

3.0

5.0

0.3

Medium

0.9

3.0

5.0

0.3

Low

0.6

3.5

6.0

0.3

Collector

High

0.8

3.0

5.0

0.4

Medium

0.6

3.5

6.0

0.4

Low

0.4

4.0

8.0

0.4

Local

High

0.6

6.0

10.0

0.4

Medium

0.5

6.0

10.0

0.4

Low

0.3

6.0

10.0

0.4

 

Small Target Visibility - Recommended Values

 

STV Criteria

Luminance Criteria

Roadway & Pedestrian Conflict Area

Weighting AverageVL

Lavg cd/m2

Median < 7.3m  

Lavg cd/m2

Median ≥ 7.3m

Uniformity Ratio

Lmax/Lmin 

Road

Pedestrian Conflict Area

Freeway Class A

 

3.2

0.5

0.4

6.0

Freeway Class B

 

2.6

0.4

0.3

6.0

Expressway

 

3.8

0.5

0.4

6.0

Major

High

4.9

1.0

0.8

6.0

Medium

4.0

0.8

0.7

6.0

Low

3.2

0.6

0.6

6.0

Collector

High

3.8

0.6

0.5

6.0

Medium

3.2

0.5

0.4

6.0

Low

2.7

0.4

0.4

6.0

Local

High

2.7

0.5

0.4

10.0

Medium

2.2

0.4

0.3

10.0

Low

1.6

0.3

0.3

10.0