 Interchanging with I-35W south of downtown Fort Worth, I-20 heads east towards Dallas passing through Arlington, where it is also known as the Ronald Reagan Memorial Highway.From Arlington, I-20 passes into Dallas County at Grand Prairie and heads east in to Dallas, interchanging with I-35E south of downtown and I-45 shortly after.I-20 intersects with I-635 (where it completes a three-quarter loop around the city) on Dallas' southeast side before heading east towards East Texas.