A. Horizontal Curves On steep down grades, the minimum curve radius should be increased by 10% for each 1% increase in grade over 3% as given by equation below: Tangent length = R tan (I/2) Arc length = RI B. Vertical curves & C. Stopping Sight distance (SSD) Where: RT – Reaction time, d – Longitudinal deceleration factor, and g1 – Longitudinal grade The relationship between the radius of the curvature, R(m); the stopping sight distance, SSD(m); and the off set, M(m) is as follows: Note: use this formula for M only when SSD is less than or equal to the circular curve. Angles in degree. Table C.1: Coefficient of deceleration (d) or longitudinal friction factor (fL) Vehicle type Coefficient of deceleration(d) or Longitudinal friction factor(fL) Typical use Cars 0.46 Absolute maximum value for stopping sight distance on sealed rural roads 0.36 Desirable maximum value for stopping sight distance for most urban and rural roads Trucks 0.29 Maximum value for truck stopping sight distance for most urban and rural roads Buses 0.15 Desirable maximum for passenger comfort approaching bus stops D. Design traffic Table D.1: Average SAR per axle group for project traffic load distribution Pavement Damage type Damage exponent (m) Damage Index Value Granular pavement using Figure 8.4 Overall damage 4 ESA/HVAG 0.80 Mechanistic design of flexible pavements Fatigue of asphalt 5 SAR5/ HVAG 0.96 Rutting and shape loss 7 SAR5/ HVAG 1.67 Fatigue of cemented materials 12 SAR5/ HVAG 18.9 E. Bituminous road surfacing