- A603 between A5140 and B562 Eastcotts Rd, Bedford (Grid ref TL059489)
- A603 between B562 Eastcotts Rd and A5134, Bedford (Grid ref TL072485)
- A603 between A5134 and A421, Bedford (Grid ref TL080485)
- A603 between A421(T) and A1, Bedford (Grid ref TL102492)
- A603 between A421(T) and Bedford boundary, Bedford (Grid ref TL102492)
- A603 between Central Bedfordshire boundary and A1, Central Bedfordshire (Grid ref TL145491)
- A603 between A1198 and M11, Cambridgeshire (Grid ref TL400549)
- A603 between M11 and Gough Way, Cambridgeshire (Grid ref TL430576)
- A603 between Gough Way and A1134, Cambridgeshire (Grid ref TL440574)
- A603 between A1134 and A1307, Cambridgeshire (Grid ref TL453576)
- A603 between A1307 and A1134, Cambridgeshire (Grid ref TL458584)