Jan Kupec, CERA's chief geotechnical engineer, combines three talents the latter two not often found in engineers: he knows his stuff, he has a sense of humour, and he is good at explaining what he knows. CERA have a video online in which Jan explains liquefaction in the Christchurch context.
The video shows the Avonside loop part of Avonside Drive and also Porritt Park. At about 3:50 into the video the issue of Retreat Road being split into Red and Orange is discussed. The now famous cream sponge cake explanation is also shown.
The video is here.