DUST PREVENTION AND EOAD PRESERVATION. 
17 
tion that small transverse cracks had developed where the grout had 
broken loose from a course of brick. 
Beginning with March 4, 1912, regular counts of traffic on the Con- 
necticut Avenue sections were made. The census is taken every 13 
days for a 24-hour period. A tabulation of the maximum and average 
of each class of traffic for the second one-year period, or 28 counts, for 
the period March 10, 1913, to February 24, 1914, is given in Table 19. 
The east side of the road carries outgoing traffic and the west side in- 
coming traffic. 
Table 19. — Volume and character of traffic on Connecticut Avenue north and south of 
Bradley Lane and west on Bradley Lane. 
Vehicle. 
Loaded one-horse 
wagon 
Unloaded one-horse 
wagon 
Loaded two-horse 
wagon 
Unloaded two-horse 
wagon 
Loaded four-horse 
wagon 
Unloaded four- 
horse wagon 
One-horse pleasure 
vehicle 
Two-horse pleasure 
vehicle 
Rubber-tired horse 
vehicle 
Saddle horse 
Motor cycle 
Excessively heavy 
vehicle 
Motor runabout 
Motor touring car... 
Loaded motor dray. 
Unloaded motor 
dray 
North. 
Maximum. 
East 
side. 
37 
17 
West 
side. 
17 
24 
80 
26 
3 
2 
14 
2 
3 
8 
18 
22 
35 
151 
32 
Average. 
East 
side. 
West 
side. 
South. 
Maximum. 
East 
side. 
22 
29 
28 
81 
4 
3 
29 
5 
3 
11 
20 
3 
50 
226 
19 
West 
side. 
85 
25 
3 
4 
26 
6 
4 
7 
20 
22 
51 
229 
31 
Average. 
East 
side. 

25 
130 
10 
West 
side. 
West on Bradley Lane. 
Maximum. 
East- 
bound. 

2 
6 
2 
22 
106 
10 
West- East- 
bound, bound 
Average. 
West- 
bound. 
EXPERIMENTS ON ROCKVILLE PIKE, MARYLAND. 
TARS AND OILS— SURFACE TREATMENT. 
The principal purpose of these experiments was to demonstrate the 
relative value of several bituminous products commonly used for 
surface treatment, and to ascertain, by comparative service tests, 
the relative economy from a maintenance standpoint of cold treat- 
ment with the lighter products as compared with hot treatment in 
which some of the heavier products were used. Incidentally, the 
relative wearing qualities of trap-rock screenings and fine gravel will 
be practically tested, and on some of the sections where oil was 
applied, an attempt was made to learn what difference, if any, would 
result from making the application to a wet and dry road surface. 
41701°— 14 3 
