This paper contends that in many real-world situations, the frequency
with which transactions take place is central to the relationship betw
een land prices and location. It will therefore be argued that an appr
oach which makes the transactions and journey frequency endogenous to
the cost problem is the correct way in which time should be incorporat
ed into many urban rent-distance models, Under these conditions, it ca
n be shown that a convex distance-rent gradient can be generated witho
ut the need for the assumption of a convex indifference curve or isoqu
ant, Furthermore, in many such cases, the convex distance-rent curve c
an be shown to exist irrespective of whether transport costs are conca
ve, linear or greater than linear with distance, Real examples will be
used to illustrate the problem.