【正文】 Average Absolute Average Absolute Average Absolute Division (%) (%) (%) (%) (%) (%) 1 2 3 4 5 None None 6 7 8 ODOT The indepth analysis of quantity estimating error was performed at two ,the error in the six pay items of interest was assessed by ODOT purpose of this analysis was to determine if individual division design groups had issues estimating the quantities of a given divisionbydivision analysis also reflects design and construction preferences that may not be a reflection of the statewide second level was to rollup the division errors and calculate a statelevel error for each of the six pay was done to assess quantity estimating issues across the state and reflect ODOT design and construction ,the pay item errors were evaluated on an average error and absolute error average error is merely the mathematical average of all the errors in the absolute error accumulated the sample error without regard to example,the average error for an item that had one project with a 50% overrun and another project with a 50% underrun would be 0,indicating that the engineer’ s estimated quantities were perfect when in fact there is a serious absolute error for the same twoproject sample is 50% and accurately reflects the actual estimating absolute error also more closely reflects the unbalancing issue because contractors will unbalance pay item unit prices to account for both ,the inference can be made that a high absolute error in a pay item correlates to a high probability of triggering unbalanced unit ,an agency like ODOT could have a low level of cost growth due to quantity overruns and still have an estimating problem because the low cost growth is arrived at via pensating errors. Results of the Research Table 3 shows that quantity estimating errors are greatest in the tack coat pay item with three of eight divisions experiencing an average error of25% which is the point where ODOT specifications permit a renegotiation of pay item unit infers that these three divisions will need to renegotiate the unit price of tack coat more often than the rest of the division in the , in all divisions where the average error is negativeindicating an underrun(.,the engineer overestimated the quantity so the contractor install fewer units than the number the bid quantity).From a standpoint of triggering contractor unbalancing,underrunning the bid quantity is the more dangerous of the two the study did not have access to contractor bid data,the fact that all ODOT divisions are overestimating the actual quantity of this pay item would logically lead to mathematically unbalancing away from this pay item to protect fixed costs and coat also has the highest average and absolute error on a statewide basis,which makes it the pay item most often misestimated. As previously stated,this study did not have access to actual contractor bid data to identify if unbalancing had occurred as a result of bid quantityestimating ,the FhwA requires that bid be analyzed for unbalancing using a percentage system that is established by each state [Federal Highway Administration(FhwA)2021].Both the Washington state and wisconsin DOTs use the same percentage range to determine whether a pay item has been “ significantly” unbalanced and hence may choose to reject the bid using the following definition: An individual bid item will be significantly unbalanced if the difference between the low bidder’ s unit price and the estimate, is greater than+50or75%(WSDOT2021b). Therefore possible unbalancing in ODOT bid items can be analyzed using this accepted definition. Table of Unbalancing in Tack Coat Unit Prices in the April and June 2021 ODOT Lettings Engineer’ s estimated Low bidder’ s Highest unit Low bidder’ s Highest unit Tack coat unit price unit price price bid unit price % of price % of ($/gallon) ($/gallon) ($/gallon) engineer’ s unit price engineer’ s unit price Table 4 shows the results of the analys