 The final design of the bridge included three cylindrical voids ( holes ) of 2 @.@ 7 m ( 8 @.@ 9 ft ) , 1 @.@ 7 m ( 5 @.@ 6 ft ) and 1 @.@ 1 m ( 3 @.@ 6 ft ) on each side on the bridge . This reduced the weight and pressure on the crown and the bridge is still in operation today , however it can only be used by pedestrians . The Theory of Arches and Pontypridd , states that as a bridge , the bridge was a failure , as it was " only eleven feet wide between the parapets and so steep that wagons had to use a ' chain and drag ' to descend from the crown . " 
