Engineering design tools

Computes finished elevations along a straight vertical grade at any station or fixed interval, including pavement-edge and shoulder-edge elevations for a standard crowned cross-section. It is particularly useful for land grading, gore areas, intersections, and roundabout design.

Computes finished elevations along tangent grades and parabolic vertical curves at any station or fixed interval, providing accurate roadway profile elevations. It also verifies crest and sag curve designs against stopping sight distance requirements for the selected design speed. See also the horizontal curve radius calculator for the matching plan geometry.

Calculates the minimum radius of a horizontal curve for 4%, 6% and 8% superelevation and design speeds ranging from 20 kph to 130 kph.

Calculates the superelevation runoff and tangent runout lengths per the AASHTO Green Book for single carriageways, interchange ramps and dual carriageways, on left-hand and right-hand curves, with any number of lanes. Gives the chainages of the key cross-sections (NC, LC, RC, PC, FS) and draws the plan view, edge profiles and cross-sections with the axis of rotation. Pairs with the minimum radius calculator.

Determines the required acceleration and deceleration lane lengths based on AASHTO Green Book criteria. It considers highway and exit/entry curve design speeds, average running speeds, speed differentials, and grade adjustment factors to calculate the appropriate speed-change lane length. The calculator also displays the applicable AASHTO tables and highlights the selected design condition for easy reference and verification.

Calculates and verifies the required stopping sight distance for roadways under different grades, including both ascending and descending conditions. It also determines decision sight distance for locations where drivers require additional time and distance to recognize, react to, and respond to unexpected or complex situations. The calculations are based on applicable AASHTO Green Book criteria.

Calculates the minimum clear offset required from the inside of horizontal curves to provide adequate stopping sight distance. It helps identify sight obstructions such as cut slopes, walls, barriers, and other roadside features. Particularly useful for highway, tunnel, and mountainous road design where visibility around curves is restricted.

Calculates the additional pavement width required on horizontal curves to accommodate the off-tracking of vehicles. The tool considers curve radius, wheelbase, and design vehicle characteristics to determine the required widening. Useful for highway geometric design, particularly on sharp curves and mountainous roads.

Calculates the minimum sight distance required for a vehicle to safely overtake another vehicle on a two-lane highway. The tool evaluates the required passing distance based on design conditions and helps determine whether adequate visibility is available. It can assist in identifying passing and no-passing sections in accordance with AASHTO Green Book criteria.

Calculates the sight distance a driver stopped on the minor road needs to turn left, turn right or cross the major road safely, and the sight distance for a left turn from the major road, using the AASHTO Green Book time-gap method. It gives the sight triangle legs along the major road so the clear sight area at the intersection can be checked and kept free of obstructions.

Calculates the design Equivalent Single Axle Loads (ESALs) for flexible pavement from the daily truck traffic, axle types and loads, using AASHTO load equivalency factors and traffic growth over the design life. The ESAL data can be saved and imported into the Flexible Pavement Design Calculator for its design and report.

Evaluates Single, Tandem, and Tridem Axle Load Equivalency Factors (LEFs) using AASHTO pavement design tables and calculates cumulative Equivalent Single Axle Loads (ESALs), including traffic growth over the selected design period. The calculator determines the required Structural Number (SN) and designs the asphalt, base, and subbase layer thicknesses based on cumulative ESALs, subgrade CBR, reliability, drainage conditions, and other AASHTO design parameters. It provides a safe, economical, and practical flexible pavement structure for the selected design life. The calculator also generates a comprehensive design report explaining axle load equivalency factors, traffic loading, ESAL calculations, Structural Number determination, and the complete flexible pavement design procedure.

Calculates the design ESALs for rigid (concrete) pavement from the daily truck traffic, axle types and loads, using AASHTO rigid pavement load equivalency factors and traffic growth. The ESAL data can be saved and imported into the Rigid Pavement Design Calculator for its design and report.

Evaluates Single, Tandem, and Tridem Axle Load Equivalency Factors (LEFs) using AASHTO pavement design tables and calculates cumulative Equivalent Single Axle Loads (ESALs), including traffic growth over the selected design period. The calculator determines the required thickness of concrete slab based on cumulative ESALs, subgrade CBR, reliability, concrete strength and other AASHTO design parameters. It provides a safe, economical, and practical rigid pavement structure for the selected design life. The calculator also generates a comprehensive design report explaining axle load equivalency factors, traffic loading, ESAL calculations, concrete slab thickness determination, and the complete rigid pavement design procedure.

Calculates the cost estimate for single and dual carriageway roads based on user-defined cross-section geometry, including carriageway and shoulder widths, embankment side slopes, pavement layer thicknesses, subgrade, and embankment thicknesses. The program also allows users to add quantities and rates for road furniture, drainage structures, culverts, bridges, and miscellaneous items not covered under the main road components, providing a comprehensive project cost estimate.

Calculates quantities of a box culvert from user-defined culvert barrel dimensions and standard headwall geometry (parapets, wing walls, aprons, and toe walls). Calculates the structural excavation, concrete (above ground, underground, and elevated), lean concrete, reinforcing steel, and riprap quantities. The calculator also estimates construction costs using user-defined unit rates.

Calculates quantities for multiple box culverts from user-defined barrel dimensions and standard headwall geometry, with culvert data imported from a CSV file and unit rates provided in a text file. The calculator determines structural excavation, concrete (above ground, underground, and elevated), lean concrete, reinforcing steel, and riprap quantities for each culvert and the overall project, and estimates construction costs using user-defined unit rates. For a single structure, use the single box culvert quantities calculator.

Calculates stormwater runoff from rainfall intensity, catchment area, and runoff coefficient, then designs the required pipe or channel size using Manning’s equation. Useful alongside the box culvert quantities calculator when sizing and costing road drainage crossings.