DUST PREVENTION AND ROAD PRESERVATION, 1916. 89 
TaBLE 43.— Materials and cost data for surface retreatment in 1916. 
i xperi- 
tem. (asphaltic con 
petroluem). Paint) : 
SoS SDE SSAA LA a NAS ae et TSS eae square yards. - 7, 625 13, 235 
Quantity of material per square ee 
Ai OUS TH ALCTTAN se) esa ys ee aks Oo ean yee ie | RU gallons. . 0. 23 0.33 
GOSS SU aL ARS ad BASU ot AE erate piesa oe lst cans ee CUubicyyardses|Ss-eneeeeee 2 -0115 
EYAL SEA SE USER Se OU 5; OSU rae am reece ef eT ONCE en PeMLAE AU Are dos A(T WED aa a 
Cost per square yard (cents): 
[Nee CUIS Tite hen EW ees es RES Eas Soe ae er mete SME Rima Ala Va 2.52 3.06 
CRY SESE SES 2 AEROS Payee ae ot ais, ened RRM Pa CERIN eet) 2 ARP Ap ee een 3.45 
Phelps ee amen nk i pea See eR VR BORN NL ee ee eae ce ke Ye RS ee beal al EO, Westy e Wene 
Cleaning surface..........--.---- -10 -41 
Heute MALETIAISH = oe ose te 77 14 
Applying bituminous materials - sete -35 49 
Applying sand or gravel............-..---.-2-- -18 24 
REECE STO eee ee olor ear tee es rag taie re ch ear peace ae LDN Nt AS ac 35 .36 
Motak(Ceants))\2ctiase esse 28 Se SLA: Se TNE Sa REN SOS Seen SRY | 6.78 8.15 
Experiment No. 4—Refined water-gas tar, cold application, similar 
to experiment No, 2 on Rockville Pike.—This section has not shown 
the initial signs of disintegration characteristic of section 2 of the 
pike, which is troublesome unless cared for by immediate retreat- 
ment. Several intersecting bad roads tended to impair the character 
of the surface near the intersections owing to the clay that was 
tracked on the bituminous surface. The experiment was in good 
condition, but indications were that a second application of tar 
would be required in the early summer. 
Expervment No. 5—Refined coal tar, hot application, similar to ex- 
periment No. 1 on the Rockville Puke——This experiment was in gen- 
erally good condition. It suffered a little near the cemetery, owing 
to large quantities of mud being brought upon it from side roads and 
drives. At the time of inspection there was no disintegration. 
Following the same procedure used in connection with the other 
experimental roads, a traffic census was taken on the Falls Road 
for 15 hours every thirteenth day from April 10 to December 31, 
1916. A tabulation of the maximum and average of each class of 
traffic for this period is given in Table 45. Table 44 shows compara- 
tive cost data to December 31, 1916, for the various experiments in- 
cluded in this project. The cost figures in Table 44 include the cost 
of general retreatments as given in Table 43. 
TABLE No. 44.—Surface maintenance costs »f 1915 experiments on Falls Road, Mont- 
gomery County, Md., from January 1 to December 31, 1916. 
Cost per are yard. ‘ 
Se on var Mainte- 
. Length of Saad GES GOST. 
Experiment No. Reciiaul Area. PE, | ne ied nie 
aie GED, Total. of surface. 
Feet. Sq. yds. Cents. Cents. Cents. 
4, 575 7, 625 Tete 6.25 14.02 $550. 00 
4, 386 7,310 12.11 1.07 13.12 94.16 
7, 941 13, 235 8.48 9.33 17.80 821.00 
5, 718 9, 530 9.63 -10 9.73 8.80 
5, 880 9, 800 10.21 -O1 | 10. 22 C 
