This electronic encyclopaedia, called "Road Tunnels Manual", comprises two principal parts. The part “Transverse aspects” contains 5 chapters that consider general aspects of road tunnels. The part “Operational and Safety Requirements” of the Manual contains 4 chapters and addresses particular elements of tunnels taking these requirements into consideration. The Manual ends with a Glossary which describes 200 terms and definitions translated into twenty languages.
web-based resource: http://tunnelsmanual.piarc.org/en