Pavement Design
Flexible and rigid pavement design by the 1993 AASHTO Guide — design a section for a target traffic level or check the allowable traffic for a section, with layered thickness design and built-in traffic calculators.
Open a free accountWhat it does
The Pavement Design tool sizes and checks both flexible (asphalt) and rigid (jointed plain concrete) pavements using the 1993 AASHTO Guide design equations. Work in either direction: design mode solves the required structural number (SN) or slab thickness (D) for a target traffic level, while capacity mode reports the allowable 18-kip ESAL traffic a given section can carry.
For flexible pavements, a layered thickness design distributes the required SN across surface, base, and subbase courses — honoring each layer's structural and drainage coefficients and minimum practical thickness — and estimates the section cost from a saved material catalog. Rigid design works the slab thickness from the concrete modulus of rupture and elastic modulus, modulus of subgrade reaction, load-transfer coefficient, and drainage.
Built-in traffic calculators convert current traffic into a cumulative design-lane ESAL count using a growth rate and design life — entered directly as annual ESALs or built up from ADT, truck percentage, and truck factor — and a load-equivalency-factor calculator gives the ESAL weighting for any axle load and configuration. Reliability and overall standard deviation enter the design exactly as the Guide specifies.
Everything is presented with a live cross-section drawing as you edit and a formatted PDF calculation report ready for submittal.
Methodology
1993 AASHTO Guide for Design of Pavement Structures
Capabilities
- 1993 AASHTO flexible-pavement (structural number) design
- 1993 AASHTO rigid-pavement (PCC slab thickness) design
- Design mode (required SN / D for a target ESAL count)
- Capacity mode (allowable W18 traffic for a section)
- Layered thickness design across surface, base, and subbase
- Structural and drainage layer coefficients (a, m)
- Minimum practical thickness and rounding control
- Reliability and overall standard deviation (Z_R, S0)
- ESAL traffic build-up with growth rate and design life
- ESALs from annual count or from ADT / truck % / truck factor
- Directional and lane distribution factors
- Load-equivalency-factor (LEF) calculator by axle load and type
- Saved material catalog and per-square-yard cost estimate
- Live cross-section drawing and formatted PDF report
Scope
Covers new flexible and rigid pavement sections by the empirical 1993 AASHTO method. Mechanistic-empirical (AASHTOWare Pavement ME) design, overlay/rehabilitation design, and aggregate/unsurfaced roads are planned for future releases.