Website Illustrations for a engineering consultancy firm

Information for the business: Highways, traffic and transport consultants
Industry: Business
Design details: I'm looking for a selection of illustrations for a client of mine, with hero images for their four main industry sectors, and a further simple icon / image for each of the specialist services within that sector (32 services).

Attached is a stock photo which shows the style that the client has approved, so somewhere along these lines would be perfect. There is also a screen grab attached of their work-in-progress website with this sample image in place. We particularly like the colour highlights and illustrative nature of this - it's nether too technical, nor too cartoon-like. The current image is 1100 x 410 px, so the final images should be around this ratio.

The smaller images are to be nice and simple, with use of the company's primary brand colours (grey and a dark red / maroon), perhaps with a little shading on them to give them a little depth - however, as a creative it's up to you to do something that works. I have attached some icons which were found in Google, to give an idea of what I like and the level of detail which I feel would be adequate.

Please provide some similar examples of previous illustration work so I can get a feel for your general style, or even better a proposed style or example for this specific job.

Thanks, and good luck!

Steve
Target audience: Corporate, Local Authority, Property Developers
Ideas for the visual style: Draw, Illustration
Things to avoid: Too technical, too childish
Preferred colors: grey and a dark red / maroon
Where the design will be used: Website
Extra notes: