(SAVAP International, 2013) Abubakar, Mahmud; Ndoke, P. N.
Of recent, the government of Niger state has embarked on the construction of
roundabouts with small central island rotaries; this paper compares the performance
of large central island rotaries with small central island rotaries. The performance of
large central island rotaries compares well to the performance of small central island
rotaries. Capacities of rotaries with small islands were found to be higher than
capacities of large central island rotaries while the delay for large central island
rotaries was found to be higher than that of small central island rotaries. However,
both large and small central island rotaries were found to be operating at the same
level of service. This study provides recommendations to traffic engineers and/or
planners on the conditions under which both central island rotaries perform better
and, thus, should be considered.
