# CE 370: Transportation Engineering Fundamentals

CE 370: Transportation Engineering Fundamentals
ere are some equations that will be provided to you (if needed). Please note that you
MUST know the definition of each term in the equations. I will NOT provide definitions
along with the equations.
**Power Required to Overcome Aerodynamic Resistance**
3 3
2
(horsepowers)
1100
*a*
*a*
*R D f*
*D*
*R*
*P C A V*
*C AV*
*hp*
**Coefficient of Rolling Resistance**
0.01 1 ; when V is in ft./sect
147
0.01 1 ; when V is in m/sec
44.73
*rl*
*rl*
*V*
*f*
*V*
*f*
**Power Required to Overcome Rolling Resistance**
; (horsepower)
550
; (N-m/sec)
*rl*
*rl*
*rl*
*R*
*R rl*
*f WV*
*hp*
*P f WV*
**Maximum Tractive Effort**
max
max
(for rear wheel drive)
1
(for front wheel drive)
1
*f rl*
*r rl*
*W l f h*
*L*
*F*
*h*
*L*
*W l f h*
*L*
*F*
*h*
*L*
CE 370: Transportation Engineering Fundamentals Spring 2016
**Engine Generated Power (Can be in Units of Horsepower or Metric System)**
2
(in horsepower)
550
2
1000
*e e*
*e*
*e e*
*e*
*M n*
*hp*
*M n*
*P*
**Engine Generated Tractive Effort**
where
is the overall gear reduction ratio
is the mechanical efficiency of the drivetrain
*e d*
*e d*
*M*
*F*
*r*
**Relationship between Vehicle Spped and Engine Speed**
0 2 1 is the slippage of teh drive axle (generally between 0.02 to 0.05 for passenger cars)
*e*
*rn i*
*V*
*where*
*i*
**Incorporating the Mass Factor into the Force Balance Equation**
2
1.04 0.0025 0
*m a rl g*
*m*
*F ma R R R *
**Geometric Design of Roadways**
2
Braking Distance:
2
*b*
*v*
*x*
*a*
*g G*
*g*
CE 370: Transportation Engineering Fundamentals Spring 2016
**Vertical Curves**
2
2 2 1
1 2
2
1 2
From Geometry:
– if S < L
; (expressed in percent)
200
– if S > L
200
2
*m m*
*AS*
*L A G G*
*H H*
*H H*
*L S*
*A*
**For Sag Vertical Curves Headlight Sight Distance**
If S < L
2
400 3.5
*AS*
*L*
*S*
If S > L
400 3.5
2
*S*
L SA For Sag Vertical Curves Underpass Sight DistanceIf S > L800 1 222cmH HHL SA If S < L2800 1 22mcASLH HH CE 370: Transportation Engineering Fundamentals Spring 2016Horizontal Curves2100vsVReg f Degree of Curve5729.6; (Arc Definition)50; (Chord Definition)Sin2acRDRD 1tan21801 cos211cos2cos90v v svT RL RM RE RR R MSSDR Traffic Flow CharacteristicsGreenshield’s Model1f ju ku k ]]>