1. Nomograms for selecting a message
The following nomograms are used to determine letter height, number of lanes versus number of bits of
information. These nomograms include a further factor that accounts for reading time and multiple glances to
the sign to fully understand its message.
Assumptions:
Lane width = 3.2m
Sign offset from kerb = 1.5m
Speed = 50km/h
FIGURE 1: LETTER HEIGHT FOR GROUND-MOUNTED SIGNS
FIGURE 2: LETTER HEIGHT FOR OVERHEAD-MOUNTED SIGNS
1 lane
2 lane
3 lane
4 lane
5 lane
1 2 3 4 5 6 7 8 9 10 11 12
Information Bits
300-400
200-300
100-200
0-100
5
6
7
8
9
1 2 3 4 5 6 7 8 9 10 11 12
Distanceaboveroad(m)
Information Bits
300-400
200-300
100-200
0-100