40 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 45.—Volume and character of traffic on Falls Road, Apr. 10 to Dec. 26,1916. 
Maximum. Average. 
West East West East 
bound. | bound. | bound. | bound. 
is MMoadedn -horserwa louse sees meee ee Soe See eee 16 6 3 3 
2a Umloa dedi -horsempagonee jo Rie Nc e ee ae ee eee 5 12 2 2 
St! Loaded )2-horse wagon ee ee ee eee 10 17 3 4 
4h WUmloadedt2-horse nae Omiey. oven cies ertereyeea te elcteen sere 12 4 3 2 
Oil MuOAded ANOLse Wagons ses es ee Pee en eae glee 1] 6 2 2 
Gel vUnloadedtA-horsewaronls Siete. seer mee ee eae ee 4 Siiews sewSss 1 
do 1 -horsewpleasaresvenicloes ee) soe ee cemeteries eee eae eneen 115 132 37 38 
Sulezchorselpleasurenehiclesc meses ene e ceeereee ee oeeaeeeeee 4 DL j= carmen] Oe eee 
Uiieubber-tinedihorsewehiclercesereeeeeeEereeeeeeee seer enters 3 BA sete See AMR Pe ore 
LOWES AG cl ei Ors eae eee hy eae ee ee re eee es 17 13 | 4 3 
WG MOtOnicyGlote cee Mane en nae ome aw eh neeye a Le cneee 8 6 1 1 
i2)|-Eoxcesshvely heavyiveOnicle! sec emee ease stem see eree ee eee ace 4 fh cosoeecee 1 
TSP MOton Tuna DOUbe ui ausee cease eee oe Cee eee ee See reer eee 17 14 | zi 6 
lle MEO toni bouning cane Sis o kos cee annem oe WL Shas ae é 82 93 | 29 29 
15h uoadedemobon Grayvee cues cette eee teen eee eee eee eee By 6.| 2 2 
167 |/Uniloadedimotordray- ss 5 ee eee eee eee ce ee eeeee as 2 3 leeosepotsclbosoecacos 
| 
1 Very heavy vehicles, such as carry ore, stone, timber, machinery, etc. 
BRADLEY LANE, MONTGOMERY COUNTY, MD., 1915. 
BITUMINOUS MACADAM, OIL-ASPHALT. 
Description of the original. construction of this experiment on 
Bradley Lane appeared in Bulletin No. 407, U. S. Department of 
Agriculture. The following report covers maintenance durmg the 
last year and the condition of the road in the spring of 1917. 
At the time of construction in 1915 this experiment was top- 
dressed with lmestone chips. Owing to the heavy traffic, all 
excess of this material was ground rapidly to powder and dissipated. 
In consequence, the wearing course stone became visible over the 
entire road, and in July, 1916, there was applied a surface treatment 
using a bituminous material represented: by the analysis given in 
Table 46, and, instead of limestone chips, a hard, water-worn, 3-inch 
river gravel. The quantities and costs appear in Table 47. The cost 
of this experiment to December 31, 1916, appears in Table 48. That 
the cost of maintenance was lower than that of surface treatment is 
explained by the omission of supervision and of a small distributed 
hauling: charge from the total maintenance figures. The surface re- 
quired no repairs of any kind and had displayed no weakness, except 
at one point in front of the first driveway on the south side near the 
east end of the road. Here a very small area of about 2 square 
feet showed a few web-like cracks in the spring of 1916. The surface 
at the time of last inspection was in perfect condition. No dis- 
tinction has been apparent either in appearance or wear between 
the plain oil-asphalt macadam and the sand-oil-asphalt grouted 
macadam, and henceforth the entire road will be considered as a 
single experiment, reserving necessary comment only for the grouted 
section. A traffic census has been taken on this experiment, as on 
the others in Montgomery County, and the results appear in Table 49. 
