Some clients and contractors are satisfied with the traditional delivery model while other clients mention certain problem areas and issues for concern. Still other clients prefer the innovative or alternative project delivery methods, due to the more demanding needs in today's road building projects, traffic management concerns, and the appropriate risk transfer.
Table 3 lists some of the benefits and disadvantages of the DBB model that were obtained mainly from the private meetings and from many previously published resources. This should not be considered an exhaustive list, and highlights the main issues.
Based upon the number of projects, DBB is still the main method used by most countries and the "Unit Price" is the main contract type used, except for Finland. Finland uses the "Lump Sum" contract for DBB projects, which is also preferred by many contractors interviewed in this study. The "Lump Sum" element appears to provide a potential incentive and opportunity to use innovations that can lead to potential profits. There is less debate to verify quantities and potential quarrels than unit price contracts and there is also potential freedom and flexibility for the contractors to shift payment categories/attributes to meet the total lump sum payment.
| METHOD | BENEFITS | DISADVANTAGES |
| (Traditional Model) | • Long Proven History of Acceptance • Open Competition - Large Market • Distinct Roles Are Clear • Owner Flexibility • Owner Control • Easy to Tender • Low Tendering Cost | • Innovation Not Optimized • Very Prescriptive Specifications • Usually Cost Overruns • Disputes Between Parties • Client Retains Most Risks • Incentives for Change Orders • Owner Responsible for Design Errors & Omissions • Linear & Lengthy Process • Lower Profit Margins • Contractor Cannot Affect Design |
Source: Pakkala (2002)
Table 3 DBB Advantages & Disadvantages
Most countries use the DBB model with the lowest price criteria for selecting the winning tender. Finland and Sweden do not use the low bid method, as it is important to measure the "Quality Plans" and systems of the contractor, which cannot easily be compared in a low bid environment. Both Finland and Sweden use contractor led "Quality Control" systems in which the contractor is responsible for the "Quality Control - QC" in the supply chain management.
Typically in the USA, QC by contractors is difficult and most contractors in DBB contracts prefer the "Road Authority" to make the QC decisions, as it requires competence and knowledge of Quality Control systems. Typically there is very strict inspection done by the "Road Authority" in the USA to monitor the quality during the construction process. In some cases the "Road Authority" uses professional consultants to assist QC and Quality Assurance (QA) when there is a lack of own personnel or when the "Road Authority" has the lack of experts. In Finland, Sweden, and in many Anglo-Saxon countries, most of the inspections are done by professional consultants as there is insufficient staff and project managers in the "Road Authority" to manage the QA aspects. These are usually tendered via normal professional service contracts. Sometimes it can be the same professional consultant that participated in the design and planning process and is quite beneficial as the knowledge and continuity of project is retained.