Asphalt Design Software

The Asphalt Institute has discontinued the SW-1 Thickness Design & SW-2 Mix Design software packages. There is no plan to update either software package.

See the Recommended Thickness Design Software section below for current and robust alternatives to SW-1. Regarding mix design software, many State DOTs have their own required software to be used, and several lab equipment manufacturers have alternatives as well.

The Asphalt Institute is allowing SW-1 and SW-2 to be downloaded free of charge. However, No support is offered or available for the SW-1 or SW-2 software package. Responsibility for installation and usage is accepted by the user when clicking either application’s download link below.

Application Notes

  • The files downloaded by clicking either link below is a ZIP containing an ISO CD image.
  • You will need CD/DVD drive emulation software to access the ISO file(s) to install/run the applications. AI does not endorse any specific CD/DVD drive emulation software but this Google Search results page should get you started.
  • Installers and applications are likely to run best when operated in “Windows XP SP2” Compatibility mode.
  • SW-1 will require a one-time unlock key be generated. Once the application is installed, the first time it is run, the splash screen will display an 18-digit code. Email that code to to receive an unlock key.
  • The Heavy Wheel Load (HWL) module in SW-1 has some glitches, so the Manual MS-23 should be used instead.

Application Downloads

For Roadways

PAVEXpress is a free online tool to create pavement designs using key engineering inputs, based on the AASHTO 1993 and 1998 supplement pavement design process and equations. It is user-friendly, where project designs can be shared, saved and printed. There are interactive help and resource links throughout. The PAVEInstruct learning module is a web-based pavement design education system with video instruction by leading industry experts. Go to:

For perpetual pavement design, visit: From this website, you can download the following design tools for free:

  • PerRoad 4.4 uses the mechanistic-empirical design philosophy. It couples layered elastic analysis with a statistical analysis procedure to estimate stresses and strains within a pavement.
  • PerRoadXPress 1.0 designs perpetual pavements for low- and medium-volume roads and parking lots. It was developed in response to requests by public works officials and owners of commercial property.

For Airfields

The FAA requires the use of their design procedures and software called LEDFAA.

The U.S. military (tri-services) uses PCASE.

PCASE2.09.06 Desktop is software for the design and evaluation of airfields and roadways according to Tri-Service Criteria.