The original forecasts for traffic intensity on the road section may have not warranted a four-lane road improvement (para. 13). While the PCR listed an economic downturn in Uzbekistan for this, the validation notes that the methodology followed for the estimation of traffic intensity at initial appraisal, contract completion, and reappraisal was poorly structured. Estimating traffic based upon extremely short surveys is known to introduce significant potential inaccuracies. This appears to be a common issue, with insufficient emphasis being placed upon traffic surveys. It is noted that a 20% error in traffic figures is highly likely when only a 1-day survey is undertaken. Such a 20% error will have a much greater impact on the overall viability of a project, than any other error in the appraisal methodology. ADB could apply international standards to traffic data collection in future, to minimize these potential errors.
Central Asia Regional Economic Cooperation Corridor 2 Road Investment Program (Tranche 2)