The most important thing to consider is visibility as one would not like to be responsible for an accident. Stick to low growing succulent plants which are colourful, waterwise and low maintenance. One can achieve a colourful entrance garden as there are many succulents with various shaped leaves and colourful leaves, Remember to plant with good compost and organic fertilizer and mulch well after planting to retain the moisture in the soil.Some plant suggestions are:
Aloe striata, Bulbine frutescens, Crassula capitella, Crassula ovata, Cotyledon orbiculata, Delosperma cooperi, Helichrysum family, Lampranthus, Portulacaryia afra prostrata, Senecio barbetonicus.