Below ‘Iter vestrum’ (latin for ‘Your trip’) enter an ‘ab’ (from) and ‘ad’ (to) name as can be found on the Peutinger map. The autosuggest feature will help to enter a known name. For some cities current day names are understood. Mind that often a ‘v’ character is used instead of the expected ‘u’ and similarly for the ‘i’ and ‘j’.
Click ‘Ostendere’ (‘show it’) to have to shortest route (‘Iter brevissimum’) displayed.

Try for example ‘Paris’ and ‘Mainz’ or ‘Arbor Felix’ and ‘Roma’. The route will be shown as can be found on the Peutinger map.

Start here.

I never realised the romans built so many motorways.

You´ll be amazed how many “modern” roads are still following the old Roman ones. Or how many towns still stand on were they were originally founded.