Future increases in traffic will have to take into account the limitations of the existing road, which features various areas lacking passing lanes (especially problematic if cars are held up behind slow coaches on the steeper sections), a number of one-lane bridges and a narrow carriageway width. Homer Tunnel is a traffic-light controlled one-way route during peak summer periods, as it is not wide enough to allow coaches to pass each other (though passing bays are provided). Improvements to both the road and Homer Tunnel are planned by Transit New Zealand, though a widening of the tunnel is considered unlikely due to the high costs involved.