To start, to Concrete Ontario and its members, #SafetyMatters. This is an excellent question and definitely worth reading here, as well as discussing with your potential hiring concrete producer.
If you are a Concrete Delivery Professional, it would be unusual that you would be the last person at your home plant at night. More typically it is the plant superintendent/supervisor/batcher who would be the last person at the site.
In rural / suburban plant settings, it is typically only for “special” jobs that concrete is poured into the night. In these situations – these special jobs usually involve a lot of people, both from the contractor, as well as the concrete supplier. As such – for these “unusual hour” pours, it would not be the norm that you would ever be alone on site or at the plant.
In urban city centers, there is much more concrete poured on a 24-hour clock, but again anything “after hours” is usually to special large jobs that would engage many people from the concrete supplier and contractor.
The concrete industry is committed to safety. This is an excellent question and beyond the general practices / situations described here, it makes sense to ask this question of the potential hiring producer to understand their specific situation details, policies, and support in this regard.
In addition, many hiring producers have special policies to ensure safety around their plants. Here are some examples to give you an idea, noting this is a great topic to discuss with your hiring producer:
Example 1 ~ No employees working alone in plants.
Example 2 – Mandatory buddy system for plant lockups in the evening (usually not involving a Concrete Delivery Professional).