The main form of contract used in most of the contracts is the "Lump Sum" and the "Hybrid" (combination of Lump Sum and Unit Prices). The US DOTs use unit prices, but these are for the activity based contracts that procure each activity separately. The Hybrid model can be considered quite a wise choice for using a combination of those lump sum activities, and having unit prices for those unknown activities or risks. This helps to minimize the unforeseen risks on activities such as guard rail repair & replacement, signs, and other high risk items. However, if long term contracts are used then the risks are more balanced to compensate for those unforeseen activities.
Table 12 shows the main contracting practices used by the countries and shows the contract type, duration, typical activities included in the contract, "contractor selection criteria", quoted savings, and any special notes or comments.