Roads are either highways, main roads, local roads or connecting roads, according to the nature of the traffic in question.
Highways, numbered from 1 to 39, serve national and inter-provincial long-distance traffic.
Main roads, numbered from 40 to 99, complement the national road network and serve provincial traffic.
Local roads, numbered from 100 to 999, serve local traffic and provide connections to highways and main roads.
All other roads outside the above-mentioned road categories are connecting roads.
Marked with a four-digit identification code, the most important connecting roads can be included in road signage, on a case-by-case basis.
Five-digit identification codes or possibly even higher numbering for roads is only used in the register.
In addition to the above numbering scheme, Finnish roads included in the European road numbering scheme are numbered accordingly: E8 (Turku-Vaasa-Oulu-Kilpisjärvi), E12 (Helsinki-Tampere-Vaasa), E18 (Turku-Helsinki-Vaalimaa), E63 (Turku-Tampere-Jyväskylä-Kuopio-Kajaani-Sodankylä), and E75 (Helsinki-Lahti-Jyväskylä-Kemi-Rovaniemi-Utsjoki).
The E-number for highways is only regarded as an additional number and type of route sign, since the signage for all Finnish E-roads also includes the national road number.
