Urban Semi-trailer

Project output

Development and testing of a prototype urban semitrailer with path-following steering system and hydraulic regenerative braking system.


  1. The best way to improve fuel consumption in urban delivery is to increase vehicle capacity wherever the logistics operation allows.
  2. Regenerative braking can give substantial further benefits, but the costs are significant.

% fuel saving

  1. The payload increase enabled by the trailer steering provides up to 33% saving in fuel per unit of freight task.
  2. The regenerative braking system provides a further 9 – 18% reduction in fuel, for urban conditions, depending on the drive cycle.
  3. The overall fuel reduction is 35 – 42%

% CO2e Saving

% Carbon savings for these measures are generally equal to the fuel savings.

Cost of implementation

The business case is yet to be made. Costs of commercial systems need to be determined.

Implementation strategy

  1. Consider all ways to increase payload, while maintaining fill
  2. Trailer steering can be implemented now, for niche operations. Ask David Cebon for details <dc@eng.cam.ac.uk>
  3. Regenerative braking needs further development and may notgive the necessary payback at current fuel price levels.


  1. Midgley, W., et al. (2013), ‘Modelling of hydraulic regenerative braking systems for heavy vehicles.’ IMechE J Auto Eng 227,(7): 1072-1084.
  2. Midgley, W. and D. Cebon (2014), ‘Control of a Hydraulic Regenerative Braking System for a Heavy Goods Vehicle.’ sub to Proc. IMechE, Part D: Journal of Automobile Engineering, 25 Dec, 2014.
  3. Midgley, W. and D. Cebon (2014). Design and Specification of Hydraulic Hybrid System for HGVs. Proc HVTT13. R. Pearson. San Luis, Argentina, October.
  4. Midgley, W. J. and D. Cebon (2014). Coast-down Testing of Heavy Goods Vehicles. Centre for Sustainable Road Freight Technical Report CUED/C-SRF/TR06,ISSN: 2054-4081,University of Cambridge.