Show LOCATION AND DESIGN OF VARIOUS ROADS top ru tw rast ashow q on the r als of gurval wes CROSS SECTION USED WED ON SIDE hill CURVES TO PREVENT SKIDDING of VEHICLE 3 EROSION of THE SLOPES rio P 1 azz bel J CROSS SECTION BUM mahl DITCH BUILT above SLOPE M pf 0 f tb he d ch ich at r ty by ih thil of walar t to ba caca 1 ed a 11 y is 14 10 I 1 24 6 bout it i prepared by th the united states depart merit ment of agriculture tho the A width edth to accommodate softly ano lines of average horne horse Is 14 feet aud for auto traffic tho the width should bo be not IMS less than 18 fatt though a width of 10 feet li 1 frequently in ili order to maintain tho the way ny to the required width and to afford proper soft guards against acci accident denN it 1 it to provide a shoulder tr not iris than chri alino 0 or four feet ni vide tile alone along each bide side of tho the road roadway tay proper the r hould ra rs rony may ila ahmo hmo e a botne hat lint steep cr er crown than tho the rest of the road tur surface face L t they should bo be hat flat not to endanger frallic using thoun and should constitute nn an leonal width of ro roadway aday thie this that tho tile total width of roada bei be side ditches never should bo be less than 20 feet where horse drawn traffic Ire t dominates and 24 feet where here any considerable volume of automobile frallic Is to lie ie accommodated achere here harp curves occur in the align alignment men it la in desirable though not tUt tomary to increase the width of the way A vehicle being bruun along n curved road hinds to occupy nn an appreciably greater width than where the road is fn straight and anti unless the width of tho the traveled way Is increased corre this len ten dincy contributes materially to the hazards that invariably accompany sharp cunee cumes the minimum widths given above should also be increased on embankments of any considerable depth so ns as to make ea ouster eader der and at the same time diminish the danger of accidents the width of right of way required n to provide all necess necessary pry area for the ro roadway aday slope slopes and ditches cries considerably with willi tho the natura nature of the topography grades oradea la in a public road one of the most problems to solve prop properly cir Is the question of maximum allo allow able grades in deciding this question the advantages to be rained gained by reducing all of the steeper grades on a particular road to a given maximum should be weighed against the addla inal cost which the reduction in tavea the tle following data and suggestions ate intended to aid individual judgment which necessarily must bo be thu the vitee factor in solving this important 1 the cost of pilferage ft il crago plen pleasure jure trot ric lie hor horse sc drawn draun and motor Is roily relly by grades of not more than 0 or 7 per cent sir air or seven feet line per feet measured horizontal ly provided the tile conditions condition tiro are such that it Is unnecessary to apply the brakes to vehicles alien descending tle bradex hut but for truffle where loads nio are aa as important as speed even very light grades nicy mey be of considerable disadvantage 2 the steepness of a grade decreases in three dIal luct ways the load a horse can haul a for character of surface tho the required or pull per ton of load ie Is increased by about 20 pounds for each cach per cent increase In creaso la in grade b the possible pull the horseman hor horse can exert Is decreased by ail an amount equal to the effort required to lift bis his own weir weight lit through the rise this amount Is to approximately equal to one one huu butt of the horse horses weight fop for each per cent increase in grade c the tile cf ef fetilde pull of the hono borve Is s reduced by the change in the kugle fingle at which the pull Is I 1 applied 8 the pull a horne horse can exert on u level road read inkles greatly with the individual animal and Is effected affected by the of bitching and the skill of the driver the character of the tile road surface also may have an important influence by affecting the security of the horse foothold tests made by the office of public rollas and arid rural engineering Ind leato that thal oc or a level road ariL rage farm horses borses untrained to the road can exert it teady pull for several consecutive hours equivalent to from to of bleir tt clr own weight without undue and that by resting at intervals of t from 1500 to COO feet hoy they con can exert a pull equivalent to about of thir els bt provided the foothold la fis good 4 the tile testa tests referred to above alao also indicate that with a well constructed vagos the pull required to move a gross TOSS load of one ton over a level road varies about as follows pounds 1 looie lavee and sand road average dry earth road varies featly Te atly ISO tinn firm arth anh or sand clar clay road 10 average gravel road no tent lar cuss arat J or macadam road 56 35 in general the judgment should be largely la in fixing the mum grade by the topography of the region which the rond tra trav emes verseL ac driling to the best current practice ft A hero here the road li Is or 1 expected to become of sufficient fent to warrant a highly Impi improved oved surface eur face tho maximum grade usually la Is fixed flied with ith rc Arence to this feature about ua fob tot lon ions s cent coystal plain and prairie regions 3 2 to 3 average rolling country 4 to t hilly or mountainous regions 6 to ol 01 S the question of minimum grade Is of importance only am the shin stile ditches tilt so should buve full fall to empty the tile that collects in fix them at a sufficiently rapid rule rate to present damage to the road ordinarily it ie Is desirable to kho gho the side ade ditches a fall of about one foot toot per tut of length though a bome BOi what iera full fall liaa has proved satisfactory sometimes wherever changes tn in grade occur the change should be lunde funds by means of a vertical er curve and not by no an abrupt angle angll slope slopes the elope slope at which A earth will stand when faced up in a cut or placed annn depends 1 on the char octer actor of the earth and 2 on the ell mute mate in cute cuts a good quality of noir non milking clay usually will stand on a elope slope of about 15 45 degreif deg do grecs reia or a slope la Is expressed usually one horizontal to one vertical oen een ft here fairly deep freezing occurs and in some of the southern states such mot trIal hns has beu betti known to stand for man many stars on a it slope of lesa loss than ono hallio one on ott the other hand ciny clay that blakeb s very easily may require a slope of cpr to i one or even four to one on under the most faTo favorable rable condition of climate but this latter extreme Is very iizumi i it a usual slope for clay in cute cuts Is one on to one in warm climates and one and one half to one in cold climates allo in the case of embankment clay usually can be deposited on an initial elope slope of about one to one till this steep slope seldom run cun be maintained unless the material Is of an exceptional J quality and the climate very favorable ordinarily clay embankments embank mente should have a slope of about tun IM to one in cold climates and at least one and une one half to one in wann warto climates and it the clay be of questionable quality these vi luce 1 bo red um banki neut slopes require more care la in construction than excava excavation tiou elope because any tiny flattening of an embankment slope by the tile action of weather after the road Is completed ie Is very likely to damage the road surface alle the sliding eliding in of excavation slopes sopea usually does no further damage than to ol 01 the tho ado ditcher dit chef which can be reopened readily hand of average usually requires a ix slope of about two to one la in cute cuts and three to one in embankments regardless regard leea of climate moderately coarse sand mixed with ith gravel will stand on a steeper dope elope than fine fins ennd sand because the former Is 1 not so readily by the action of storm water solid rock usually an r a be bo done on on an average elope slope of ablit one on fourth to one except where the kocl roc occurs in sloping strata separated sipa mpa rated by b slippery clay me eerme ami in the latter case caso the average slope may runy bo be all touch much an one half to one or three fourths to bouc on the facci of rock cute cuts usually ere are not dressed down don to eil j an approximate ly smooth slope as Is done in borth cute cuts in excavating solid rock anif on euch such material Is 1 moved as ie is actually necessary to obtain the desired width at the tile bottom of the cut or as hns has been loosened in blasting the faces should of courso be cleared of oil all material dudici la Is loose or which might be bg loosened by y frost and aldo aide down donn upon the road stone cm usually will stand on a slope of about one to one in order to prevent damage by wash nash inc ing nil all earth elope slopes in cither either excavation or embankment should be protect ed b a growth of brass as soon an practicable after they are formed forni pd in many localities where the eoll soil 1 li 10 0 fertile nul a rood good quality of grosa grass 1 buthe no seeding eel lne of tho lopes slopes Is necessary in 1 other cases casc the soil 11 may way fajok tio fertility to grow groso even when vien the slopes are seed ed and nod in which illitch event it may be very dest to cover the slopes with cut sod mod this latter prow usually la 19 very expensive aad ud should be employed only where here it Is known that thorough seeding arid fertilizing would fall to secure a cov covering erinc of sod another precaution frequently new noce sary in order to prevent the washing I 1 away of slopes la Is to inter intercept WB wit er from the natural ground which otherwise would how flow down over the ex avallon slope this Is done by rowna of a it aberm bc nu ditch constructed ell back from front the top of the lope figure 2 illustrates a condition which makes a bena ditch desm desirable ble and aleo shows how och such IL ditch Is 1 r |