Costain expects full-year results to be in line with the board's forecasts after another strong performance.
The group said it was making good progress in its transformation into the UK's leading smart infrastructure solutions company.
It said examples of recent activity in this regard include the group's involvement in the operational trials of HGV platooning vehicles, the Government funded testbeds for connected and autonomous vehicles, and asset optimisation for a number of water utilities.
It had also appointed technology leader Jacqueline de Rojas as a non-executive director.
Costain said it continued to differentiate itself by offering integrated technology, consultancy, asset optimisation and complex delivery services to meet the ever more complex challenges of enhancing the nation's infrastructure.
It said that as a result of new orders, including further awards on the High Speed 2 programme, the group had finished the year with a high-quality order book maintained at £3.9bn (31 Dec 2016: £3.9bn).
Costain also said it had a preferred bidder position at c. £400 million (31 Dec 2016: £500n).
It added: 'Following very good cash generation towards the end of the period, the group finished the year with a strong net cash position of over £150 million (31 December 2016: £140.2 million).'
Chief executive Andrew Wyllie said: 'Costain has had another strong year. Our performance is a direct consequence of our differentiation and our ability to provide the rapidly changing range of integrated services required by our major clients.'