The final column in Table Ⅳ gives the value predicted by the logistic model for the PSREP in 1996 for each of the three count-sites. Additionally Figs 2, 3 and 4 illustrate graphically the predicted growth in the PSREP over the period until 1996. From these results it is evident that if there had been no significant change to the highway network since the reference year, 1991, then two of the principal river crossings would be operating extremely close to their realisable capacity limit by 1996. However, the opening of the new Blaydon Bridge, at the end of 1990, gave additional capacity, although the full benefits of this did not become immediately apparent as shortly after its opening another river crossing, Scotswood Bridge, was closed for a year to effect major repairs. The extra capacity provided by the Blaydon Bridge has clearly post- poned the time when major delays will start to occur. Further work is currently being undertaken to take this into account.
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