Connections for tomorrow

From the first highway to the latest transport strategy. We have been working toward a bright and successful future since 1953.

We are among the largest civil engineering companies in Slovenia.

We provide consulting services, conduct studies and research, as well as plan and design in the fields of transport, the environment, hydrotechnical engineering, civil structures, and geodesy.

We excel at the entire planning process


Total annual turnover in the last 10 years


Total investment in planned projects in the last 10 years


We have been providing new connections for 70 years

Vision and mission

Development of modern and innovative answers to the most challenging questions in the fields of transport and the environment, which support economic development and contribute to a good quality of life and the environment.

With our expertise and decades of experience we ensure that projects are successfully completed – from the initial idea to the final construction.

We offer invaluable experience

and excellence in dealing with the most challenging traffic planning and traffic infrastructure of all kinds.


Consulting / Studies and research / Designing


Virtual Infrastructure Simulation and Evaluation


We have carried out over 100 traffic, transport-economic, and environmental studies (noise, gases) …

We have secured project documentation for over 100 road, railway, port, airport, and energy supply infrastructure projects

We have secured project documentation for over 100 civil structures (viaducts, bridges, retaining walls), buildings, and hydrotechnical studies and solutions

We offer assistance in organising projects, from terms of reference to reviews and revisions, from applications for the approval of design conditions and applications for building permits to acquiring operating permits.




At the company PNZ d.o.o., we are proud of our 70-year history of planning new connections. From the first motorway in the former Yugoslavia to the most cutting-edge development strategies for transport infrastructure in Slovenia, from an idea to construction: we are distinguished by our long tradition, which we are continually building upon with contemporary skills and expertise, and the integrity of our offer. This includes everything from developing traffic models and conducting traffic studies to planning in the fields of roads, railways, ports, airports, energy infrastructure, structures, hydrotechnical engineering and traffic ecology, and allows for projects to be carried out from the initial idea to the final construction. With our long-time partners, we work on successful projects in architecture, landscape architecture, spatial planning and urban planning.

Our partners include highly reputable firms such as PTV, Ineco, AF-Cityplan, SATRA, IER, UIRS, UL-FGG, UM-FGPA, UZ-GF and IJS. Over 100 experts from various fields take part in our projects depending on the needs of each project, using the most state-of-the-art engineering and programming equipment.


  • Project preparation 
  • Terms of reference
  • Reviews and revisions of project documentation
  • Traffic safety assessment 
  • VISE

Studies and research

  • Traffic studies
  • Traffic modelling (micro, meso, macro)
  • Master plans and sustainable urban mobility plans
  • Preliminary studies, conceptual designs and variant studies of all traffic infrastructure types
  • Traffic counts
  • Surveys
  • Mobility plans
  • Environmental studies
  • Studies of noise pollution
  • Accredited procedures of noise measurements
  • Economic and investment studies
  • Feasibility studies
  • GIS data analysis
  • Visualisations


  • Infrastructure
    • Roads
    • Railways
    • Ports
    • Airports
    • Energy supply
    • Utilities
    • Other
  • Structures
  • Designing with BIM technology
  • Planning of civil structures and buildings with static calculations
  • Hydrotechnical engineering
  • Geodesy

Virtual Infrastructure Simulation and Evaluation

VISE offers road section evaluation with »human in the loop« procedure already in the design phase. Real drivers test and evaluate the newly designed section in a safe, yet equally engaging environment in a driving simulator.

  • Detect and avoid creating dangerous sections of road in the design stage
  • Increase road capacity
  • Increase safety of autonomous vehicles integration
  • Saves time and money for investor / customers
  • Includes the end user during the design phase
  • Simulations of critical situations
  • Mobile simulator allows driving evaluation anywhere and with local population
  • Reduces internal and external operational costs

We have carried out over 100 traffic, transport-economic, and environmental studies (noise, gases):

  • Starting points for arranging the Ljubljana motorway ring and access roads
  • National traffic models of Slovenia, Croatia, and Slovakia
  • Meso- and macroscopic traffic simulations for the City Municipality of Ljubljana and the Ljubljana region
  • Sustainable urban mobility plans for 16 Slovenian municipalities 
  • Mobility plan for the City Municipality of Velenje and Šalek Primary School
  • Economic feasibility of the A1-Slovenj Gradec section of the third development axis
  • Evaluation of the steps taken towards the future Slovenian transport network
  • Expert report for the Ljubljana railway hub within the framework of the RAILHUC project
  • Preparing and conducting a survey of households regarding mobility habits of the population of Slovenia on a nationwide level
  • Traffic review of the connection to the Hofer supermarket and new residential development in Domžale
  • Operational noise monitoring of Slovenian motorways and major regional roads
  • Noise pollution study with a proposal for noise barriers and a report on passive noise protection for the project documentation of the Koseze–Kozarje motorway section (widening to six lanes)
  • Noise study with a proposal for noise barriers for the purpose of reviewing changes to the municipal planning document of the Municipality of Grosuplje for the Velika Stara Vas area

We have secured project documentation for over 100 road, railway, port, airport, and energy supply infrastructure projects:

  • Motorway between the A1 in Slovenia and the A7 in Croatia
  • Motorway connection from the A1 to Slovenj Gradec (third development axis)
  • High-speed Venice–Ljubljana railway: Trieste–Divača section
  • Maribor–Šentilj railway
  • Building information modelling (BIM) of the expansion project for the Karavanke motorway tunnel
  • Numerous road infrastructure projects
  • Numerous railway infrastructure projects

We have secured project documentation for over 100 civil structures (viaducts, bridges, retaining walls), buildings, and hydrotechnical studies and solutions:

  • Footbridge across the Kamniška Bistrica in Homec
  • 4-01 overpass crossing the railway in Litija
  • 4-1 ”Pasarela” pedestrian overpass crossing the Koper–Lucija motorway
  • PZ-03 retaining wall on the Koper–Lucija highway
  • Container repair station at the Port of Koper
  • Expansion of the Šmarje Sap motorway access and exit point: a plan for surface water drainage, water management, water supply and sewerage
  • Wastewater treatment plant at the Gotenica Supply Centre
  • Supply of drinking water for the coastal region and Kras
  • Poljčane overpass: a hydrologic-hydraulic study, a water management plan, a water supply plan
  • Expansion of the Karavanke motorway tunnel: a water supply plan


  • DARS d.d.
  • Slovenian Infrastructure Agency
  • Ministry of Infrastructure of the Republic of Slovenia
  • HSE – Slovenian Power Company
  • HESS – Slovenian Hydroelectric Power Company
  • Port of Koper
  • Slovenian Railways
  • City Municipality of Celje
  • City Municipality of Kranj
  • City Municipality of Ljubljana
  • City Municipality of Nova Gorica
  • City Municipality of Slovenj Gradec
  • City Municipality of Velenje
  • Municipality of Bled
  • Municipality of Brežice
  • Municipality of Hrastnik
  • Municipality of Izola
  • Municipality of jesenice
  • Municipality of Lendava
  • Municipality of Log – Dragomer
  • Municipality of Postojna
  • Municipality of Radovljica
  • Municipality of Ribnica
  • Municipality of Sevnica
  • Municipality of Tolmin
  • Rudninis, d.o.o. (E.Leclerc)
  • HOFER d.o.o.
  • IKEA Slovenija, d.o.o.
  • LIDL Slovenija d.o.o.
  • Mercator, d.d.
  • Raiffeisen LEASING d.o.o.
  • Shell Adria Ltd.
  • Spar Slovenija d.o.o.
  • Trans Felix d.o.o.


  • Rijeka–Zagreb Motorway, Croatia
  • Belgrade Land Development Public Agency, Serbia
  • Gruppo Europeo di Interesse Economico Linea Ferroviaria Trasfontaliera Trieste – Divača, Italy
  • Institut IGH d.d., Croatia
  • Mercator-S d.o.o., Serbia
  • Ministry of the Sea, Transport and Infrastructure, Croatia
  • Ministry of Transport, Construction and Regional Development, Slovakia
  • City Municipality of Bad Radkersburg, Austria
  • City Administration for Construction Land and Investments, Novi Sad, Serbia

Main administrative office
Nataša Grašič

01 589 65 14

Director’s office
Andrej Jan, BSc and Civil Engineering

Saša Hribar

director’s sectretary
01 589 65 19

Marko Jelenc, BSc and Civil Engineering

01 589 65 40


mag. Gregor Pretnar, MSc and Civil Engineering

01 589 65 23

Miha Zupančič, BSc and Civil Engineering

01 589 65 26

Gorazd Drofenik, BSc and Civil Engineering

01 589 65 22

Hydrotechnical engineering 
Andrej Bogataj, BSc and Civil Engineering

Ervin Jezovšek, BSc and Civil Engineering

01 589 65 31


The appeals

Any interested party can submit a complaint against the work of the Company and/or the Laboratory for Traffic Ecology, namely in writing. Any interested party will be given a description of the process of dealing with complaints related to the activities of the Transport Ecology Laboratory upon written request.