Try heading out of town and you'll be hard-pressed not to cross a stretch of road that engineer Bob Smith's had a hand in.

The 70-year-old has worked on "many, many, many contracts" since he qualified as an engineer in 1969.

Of all the engineering contracts he's been involved in, Mr Smith is most proud of a four-year project realigning SH1 at the Hihitahi Bluffs between Taihape and Waiouru.

"The road was in the shadow of the bluffs ... it became very icy in the winter.


"It would stay iced all day because it was in the shade."

Working as project manager and engineer on the $20.4 million job, Mr Smith helped to move the 3.5km stretch of road away from the bluffs and out from under the shadow.

The project earned the 2007 New Zealand Planning Institute Project Award and the 2007 Roading Excellence Award.

He said it was very satisfying to complete the project: "I came off that project and thought, 'What am I going to do now?'"

Come next Thursday, Mr Smith may be asking himself that question again, although he believes he'll have enough to keep himself busy. He is retiring next week after 50 years working for Opus International Consultants, originally the Ministry of Works and Development.

He first began working for them when he was studying at Canterbury University for his degree in civil engineering.

After five decades on the job, Mr Smith felt it was time to move on.

"You just get to know when it's time to retire. Up until 18 months ago ... I didn't feel like retiring. I think the company is now going through another round of changes and it's just time for me to get out and enjoy myself."

While Mr Smith didn't have any particular plans for his retirement, he is "heavily involved" with the Rotary Club of Wanganui, and was part of a group pushing for the velodrome to be roofed.

He was also working on a subdivision in his home town of Nelson.

And if those things don't keep him busy, Mr Smith hopes to "start playing golf again" and eventually go travelling with his wife, Margaret.

"I'm happy, I'm ready. You know when you're ready. You know when your enthusiasm and your motivation starts waning a bit."

Mr Smith can look back on a career where he worked on many major projects and held a number of different roles, including manager of civil engineering for the Works Consultancy Services, where he had 35 staff.

He was also business manager for Opus from 1993 to 2000, after which he took on the role of principal engineer.

"I've had a vast variety of jobs and experience, and there's a lot of things I'm really proud of."

He said he found site investigation work hugely rewarding: "Everything we build relies on the ground to hold it up."

New Zealand's geology was "very diverse" and he enjoyed designing foundations to make sure the structures remained above ground.

Mr Smith officially retires on Thursday, and is having a farewell function on Friday.